To challenge a person's parenting at the park

Any parent sending a 2 year old off into that park (thank you for the picture @HuckleberryBlackcurrant ) and then not bothering about them is disgrace.
I don't think you did anything wrong Huck.

I think you did the right thing, the child could have been in danger.

This happened to me yesterday a very young toddler no older than two was in a pub playground and playing by a steam with long drops, rocks and slippy areas. There was also a very large slide and animals like chickens roaming. The child couldn't communicate with me so I felt I had to hang around and check on her. She then left the park area, went over a bridge, through the beer garden, across a rural road and into the pub.

I was astounded but didn't confront the parents as yes I don't like confrontation but good god there is no hope for that child

Helping your own child climb a ladder is fine.
Helping another child means you are then responsible for them while on that equipment as you have overcome the natural safety barrier.
Helping children off things or pushing them on a swing is totally different.

I'd totally help my son climb a ladder I like to teach him to do things safely rather than have him try and get stuck. I constantly help children get off things push them on the swings etc if they are playing with my son. My theory is that if the parents were that bothered they would be keeping a better eye on their kids.

Absolutelyl the right thing OP

Yabu to help a child you don't know up a ladder, ladders at parks are natural barriers. If a child can't get up a ladder they won't get down it.

I think you did the right thing. Not sure why anyone would think that you overstepped while your only concern was the safety of a child left in potential danger. Well done I would say!!

apart from the physical danger, sounds like that child could have been easily lured away.
always speak up in the cause of safety, esp re vulnerable people.
well done, OP.

You were 100% right to do what you did. The child's father sounds like an absolutely shit parent. And your DH is wrong.

I hate going to parks for this reason, always end up with a follower as wouldn't dream of leaving my young kids alone in a park. You were right to say something, but I doubt it will stop him doing it again!

I was ready to say you overstepped because kids need to learn independent play but no, I would've done the same. You didn't kick off or have a go, you said a sentence that was true and relevant and he clearly deep down knew you were right or he probably would have argued back a bit.

You don't watch a toddler from a distance ....that's utterly pointless.

I think you were totally in the wrong helping a toddler get on equipment. The basic rule is if you cab get on you can play on it. Personally your behaviour sounds busy body ish to me. We've only got your side of it. For all we know the man might have had an eye on him at all times. If he was on his phone all the time then OP only knows this as she was watching him constantly 🤷‍♀️

When I saw your thread title I thought you were probably going to be unreasonable but on reading that, I absolutely agree with you.

I'd have done exactly the same OP. And my DH would also have told me I shouldn't have. But I'm not someone who can sit back and watch disasters unfold without stepping in to help. DH is that kind of person and thinks I'm too inclined to stick my nose where I shouldn't but maybe that's why we make a good team!

The irresponsible behaviour of some parents of young children never ceases to astonish me. And when called out on it, act all offended. Your children are a precious gift. Look after them.ffs!!

I'd of done the same and have done
I can remember supervising my 5 yr old at a park which was attached to a cricket ground.
A group of about 15 kids of the same age came to the park after a party in the cricket ground,, all unsupervised.

I had to help several of them get down from the monkey bars and climbing frames. I was incredibly worried as there were no adults.
After 20 mins or so 1 adult from the party turned up and i said "Someone should be looking after these kids as ive had to help a few of them" she just replied " Only one is mine". I then left the park and the lazy parents were just outside the entrance talking.

I think I would have probably been lot sharper with the dad so you did well to stay polite

You absolutely did the right thing @HuckleberryBlackcurrant! It amazes me the number of times I see really young children unsupervised. We live in a seaside town and I was walking along the prom one day when I noticed a very young child (just under 2 at a guess) walking along about 1m out into the water with clearly sunburnt shoulders and back 😔 there were no obvious adults so I went over and got him to come back into the sand and asked him if he could tell me where his mummy/daddy etc were - he started giggling and toddled off down the beach so I followed to ensure he found an adult and found his mum & dad sitting eating a picnic about 150m down the beach 😔 The mum immediately questioned why he had no clothes on - they were sitting behind her on the sand and he was just in a nappy. And asked where I had found him because they thought that he was playing right behind them. I have no idea how long he’d been unsupervised but he was already clearly sunburned so it had been a while!

You we're very polite and he did need to be aware, my two year old went off the wrong side of the play structure last week, I was on the side with the slide and he decided to attempt to slide down the climbing wall he both managed to hold on and be caught by another mum honestly so thankful for he being right their! I couldn't imagine not having my eyes on him at the park because he is a daredevil and they are high! Two year olds need watching constantly and if he didn't realise that without being told then he might do now!

Totally fine and needed to be said. The embarrassment of an adult is insignificant to a little toddler seriously hurting themselves!