It's not really about folding/not folding, being precious about your child's sleep or whatever.
It's about showing a modicum of consideration for your fellow passengers.
If everyone is all me-me-me, why should I have to fold, why can't you wait for the next bus, why should I give up my seat to an elderly person when there is a seat at the back of the bus, I was here first, I'm more entitled to this seat than anyone else etc etc then it just makes the journey more horrible for everyone.
People just don't think, or seem to care, about the impact of their behaviour on others. It's all "Why should I modify my behaviour, if you don't like it, modify yours", and I just find that so awful, so anti-social.
It's public transport, you have to share it with other people. And if you try to be considerate of them, then you have a right to hope they might do the same - and then you have a whole busload of people who are trying to treat you with consideration rather than make your journey harder. If you don't, well, you're on your own, nobody caring about anyone else, everyone in their own little bubble.
Luckily for me, I'm able bodied, don't need to use a pushchair, can cope with standing, or with waiting half an hour for the next bus if necessary - heaven help anyone that can't, because it clearly is nobody else's problem but their own
.