Would you expect/would your family join in with the Tom foolery?

This seems unlikely - all the posts so far seem coherent.

Why are you assuming that everyone who disagrees with you must be drunk? I haven't touched a drop and I still think you're being an entitled brat.

What? It’s her house. She’s banished to her room because two socially awkward adults who knew they were visiting a house with a 6 year old relative in couldn’t be bothered to even talk to her? Don’t be ridiculous. I wouldn’t mind but these people advocating social confinement for a normal egregious 6 year old will be the same ones bemoaning the fact that children have no social skills.
Interacting with family members of different ages is normal and expected. I could understand if it was an elderly or ill relative who needed some quiet time but seriously, an 18 and 20 year old? Were they suddenly going to burst into conversation once the 6 year old left the room?

If they are quiet awkward people then something like a jigsaw is a good way to encourage interaction. It doesn't require anyone to make a fool of themselves and lends itself to easy conversation. Sometimes just a little ice breaker is needed, not everyone is a natural with kids and doing activities where you can just talk about the activity itself rather having to have random conversations or engage in imaginative play can be easier for people to do.

OP are you honestly not taking anything from this thread?

I imagine that you’ve got used to amusing your DD, constant interaction, chat, play - you used the words tomfoolery and bouncing around. As a PP said; this is toddler behaviour. Perhaps it’s continued due your DD having ADHD, but it’s really not fair to expect people to come to your house and act the same way as you. It sounds like it got uncomfortable for everyone.

ADHD or not, your DC can be taught how to leave adults alone if they’re clearly not interested, and play quietly. Your constant messaging of ‘the only little one’ ‘it’s a little girl’ suggests you do expect some level of fuss and attention, simply because of her age.

Sorry, are DN and DN your niece and nephew? If so, are they children or adults?

ETA: Have now seen their ages.

nobody would expect her to be in her room for 6 hours.

Your opening post described her bouncing round talking at people. Then you dripped the ADHD?

You need to teach her how to behave in social situations. Why did they visit? did you invite them? do they know she has ADHD? did they realise they would be expected to entertain her? So many questions

But it's ok because you have decided that everyone who has pointed out how awful this might be for your visitors are just mean girls being mean.

Your lookout if it happens again. Or they never visit again.

Do you show as much interest in your niece and nephew as you want them to show in your DD? Do you try to find common ground and know what they're genuinely interested in (not just asking generic "so how's college?" type dead end impersonal half hearted small talk)? Do you know what music they like, what causes they care about, what their worries are, who their friends are, what they do for fun when not on family visits?

Asking them to play with your daughter isn't being interested in them as people, given the twelve and fourteen year age gaps - it does sound (unintentionally/ unconsciously on your part probably) like expecting them to babysit...

Your DD is possibly a little socially ypung for her age (not unusual in a neurodiverse child) and still has a toddler's innocent expectation that everyone will want to do what she wants to do, and lack of awareness that adults (which your niece and nephew are) don't usually enjoy running around playing with much younger children, and only do it out of affection for the child.

Sometimes ND children need explicitly teaching things their peers tend to intuit, and you may need to gently explain to DD the different ways to interact with her age peers/ younger children versus adults/ teenagers.

Not for the whole six hours, no. But I don't think kids should be buzzing around for hours on end. Not only is it highly annoying for the non parent adults, it is also overstimulating for the child. I am very glad that the friends I have with kids aren't like the OP. On the contrary, they don't want to spend their adult time around their own kids!

For 6 hours?

Go to her room.

God no. What you are describing is you were exoected to parent your child to allow the other guests to be left alone. They aren't child entertainers and frankly other people's children are really tiresome after a while no matter how much you care about them

Funnily enough, one of the most enjoyable and hilarious family get togethers we’ve had recently was when my younger nieces made us all play hide and seek. Aunts, uncles, teenage children and grandparents. It was genuinely really funny and not something I’d really be bothered with usually.

Family get togethers should be about involving everyone. I’m not suggesting everyone should be playing hide and seek but you’d think some of the posters here had just emerged from the Victorian era with their views about children just playing quietly or being in their room. Surely meeting up with family means family members should be interacting. It’s difficult if there’s a sole child who’s much younger but the older teens are actually adults, not young teenagers. They strike me as very self-absorbed, awkward and anti-social. I know many teens who are more than capable of engaging with young children. OP- I’d be annoyed too

But they were there for six hours! Was the 6 year old meant to entertain herself for all of that time? Nobody else was bothering with her so what were the parents supposed to do?

Maybe they just aren’t used to kids that age, I was hideously socially awkward and self conscious as a teenager (undiagnosed autism) and even when I was a child
myself I wasn’t good at playing. I just don’t know how.

You're being incredibly rude.

I'm out.

you literally described her bouncing around. I get it - she is your child, a PFB?

Not everyone comes to see her, they come to see you. You let her bug them and now you're cross?

Nope.

OP is hilarious, most people disagree with her and there she is throwing her toys out of the pram. I actually don't really agree with the person who said the child was a brat, OP is the brat (although the child will probably grow up to be insufferable if OP is anything to go by)

Me? I have two children, one with ADHD as it happens. I still always expected decent behaviour from them and for them to not hassle or pester guests. Absolutely my ADHD child needed more interaction (from me/DH) than the NT one, but we taught him strategies (fidget spinners, mind exercises, climb the stairs a few times etc ), we didn't try to change the environment or other people's behaviour, because that's not a realistic long term strategy.

How rude and obnoxious. You don't even know these people.

Yes to Snap! A few games of snap and a few games of cheat, that thing where one of you draws the head, and folds the paper and then then next person draws the body - make some paper aeroplanes, maybe a basic board game, she helps set the table and clears up, takes a drinks order, hands around a plate of biscuits - it’s not a choice between “hide and seek” and “seen and not heard” but she should be able to entertain herself for some of the time. You should have helped her by suggesting some activities she could easily join in rather than let her get upset and then leave your guests to go out to play.