I feel naked if I go out for even a short ride without a helmet on! I've done it a few times in the past, and wow it feels wrong. When I first got into cycling in 2020, I didn't have a helmet for the first couple of months or so. Where I found the bravado for that I have no idea, I've had to turn back when I realise I have no helmet on before now and I think that's just sensible.
I could understand a prejudice against helmets if they were really expensive, but they're not. I have two helmets, one is a £15 helmet from Asda and the other is a £69 Kask helmet I picked up in a local pro-level cycling shop. I use my Kask helmet when I'm on a non-commuting ride, primarily because I have no trust in leaving it anywhere at work. I don't like leaving my cycle at work, even with a high-quality lock in use, so it's a rare event for me to cycle to work. I'm close enough that walking is a reasonable option though, so that's not so bad.
Would I recommend helmet wearing being a legal requirement? Honestly, I don't know. There are pros and cons to it being legally required, as already mentioned by others. I'd like to see more people leave their cars behind and take up cycling, so I'd not want to do something that stops that. So I think I would leave the law as it is right now, it only seems logical to let people choose. The preferred option is to focus on providing good quality routes, which would no doubt help encourage more people to go out on two wheels rather than their polluting 4-wheel machines.
Now if we were talking about making lights mandatory, I'd absolutely be up for that, and making it mandatory to have good quality lights too. So many of them I've tried are just not sufficient, even when used in combination with bright clothing, there needs to be some sort of minimum standard.