To not understand why double barrel surnames are so wrong/bizarre to some people?

You have a quite specific situation where one name was much easier in your particular circumstances than the other then. Which means the principle you chose to apply there isn't going to be relevant in many cases, including in the example you gave. Fitzsimons can have one m or two, after all. Ultimately, avoiding what you describe as 'ridiculous form filling' means some people would need to change names entirely. That in itself is at best a ridiculous concept for many of us, and at worst something rather more nefarious.

I grew up with a double-barrelled surname.

Ditched it for husband's much shorter one as fast as possible.

Nowadays I think people just assume that kids with double-barrelled surnames have parents who aren't married, but I had decades of people assuming I was wealthy, posh, stuck-up before I even opened my mouth or met them. No way would I have landed my kids with one.

And the past is a perfectly splendid place for them to remain.

I actually have a surname as my middle name but my parents would certainly not have added a hyphen between it and my surname. It would have been odd to do so. Tradition is clearly a thing of the past!

Not in my experience.

I think children should be able to choose their gender and name when they are a teenager. Until then they can be known as MX and the number of their birthdate.
This will stop outdated stereotypes being foisted on children.

Obviously not. But I have a "forrin" name. And it's a pain in the ass. DH's name isn't easily spelled. Double-barrelling them for my child would have made his life difficult, so DH and I chose one of our names.

In the example you give, anyone with a surname as non-Anglo and relatively uncommon as Kiriakopolous (ie not something like Singh which everyone knows) is potentially going to have a lifetime of spelling it anyway.

This principle would essentially mean that those of us who are a bit forrin, and actually quite possibly even British people who want to use names from Celtic languages but can't guarantee that their kids won't want to live outside of those areas, shouldn't be using those names. I doubt you actually think that.

Lots of people with only the one surname have a first name and surname that combine to make a very lengthy name. My surname is 14 letters alone. The argument that people should stick to one surname because it's a pain for others to write is a tad weak honestly.

People don't typically choose names based on what's easiest for Sharon in IT to type out on her computer.

Tbh I think it's also an age thing. Mumsnets demographic are of an age where in their time it likely was maybe a bit aspirational or a sign of being higher class but you're blind if you believe for a minute that this is still the case. It's absolutely rooted in equality for women these days.

I can quite confidently say that if you asked any random teen or 20 something year old why they think people choose DB names, 95% would answer along the lines of "because it's what is most fair to them". This entire thread is just a testament to how out of touch a lot of people on this site are.

Double-barrelling is all well and good when you and your partner have short, easy to spell names. Daniel Jones-Butler works and it's not setting a child up for a lifetime of ridiculous form-filling and having to spell everything. Daniel Fitzsimmons-Kiriakopolous is a whole other ballgame.

OP is married.

Everyone I know who has given their child a double barrel name is married or at least in a long term committed relationship. In my experience its usually the women blindly giving their children dad's surname alone that tend to be stereotypically 'unclassy'.

I associate it with lower class people, not the aspiring middle class as has been suggested above.

OP:
They have become something that some people use because they are unmarried. In the past they were used to denote the joining together of two aristocratic families but these days they are tagged on to names like Demi, Jai, Harper7 etc. Not classy.

I don’t see DBing as a class issue - it’s very much a feminist issue these days. The people saying otherwise sound like incels trying to take women down a peg or two.

Historically when women married they belonged to their husband and didn’t have the right to vote or own property etc. So while it’s traditional to take the man’s name, it’s for all the wrong reasons.

Why in this day and age should a woman automatically take her husband’s name, and why should their children not also carry their mother’s name?

DBing isn’t a perfect system as inevitably the next generation will have to drop a name when they get married so as not to triple or quadruple barrel. However it is much more equal.

If people want to take just one name they prefer then that’s fine too. Point is it should be a personal choice not open to judgement and criticism.

shiny Range Rover driving, Labrador-owning, skiing set

Jesus I missed that, what's wrong with skiing now?

This is hilarious.
I don't have a labrador (or any pets), can't ski (no interest in sports), and don't darling anyone. I don't drive and I don't care much what people think of me in general.
The other DB people I know. One rides a bicycle, works for a bat rescue group and plays in a folk band. The other is self-employed and doing quite well for themselves.

As others have said, in other cultures it is not unusual.
Perhaps some form of inverse snobbery or judgy-pantery is at play?

People should use whatever name they are comfortable with using. Doesn't matter if I like it, or would choose to use it for myself, its not my name and not my business.

ffs just pick a fucking name. Two names. First name. Last name.

Oh how shocked you will be when you find out about middle names...

My DC have 2 parents. We both have our own last name - the ones we got when born. No, mine isn't a loaner name any more than his is. Why would we want to actively drop one?

MN on class never disappoints!

Probably is.

No-one bats an eyelid about my DD's name until they realise we both are British.

My DD actually has friends whose parents come from Spain, Portugal etc. so they gave multiple names.

Added to that people in London and cities are more likely have been in contact through education and work, or be friends with Europeans who have multiple last names.

Plus lots of other nationalities
don't follow English naming conventions e.g. you keep the name you were born with through out your life.

Lol. All the Range Rover types at my kids school gave their kids their dads name. It’s just me with my feral mongrel and pos car who double barrelled.

Not my experience at all.

But in non leafy S London we have high density social housing and non-range-rover owning professional / media / teacher types who are all equally as likely to give their kids the names of both parents.

I wonder if it is regional?

A third of kids in my DC’s schools had hyphenated names. S London. Amongst DC’s friends, A mix of single mums, married, co-habiting, and spanning working class and m/c professionals alike. It is considered pretty normal.

You people have such wild imaginations.

Are these try hard, range rover driving, Labrador loving people in the room with us now?

Lol. “£50 from my father”