I am really really sorry to go off-topic here, but as an European this is... So strange and slightly hilarious to me. We went to a park. Or local river/lake.
A mall would have been a useful place to hang out because it's under a roof and there are things to do, but there were very few good malls in that part of the UK and anyway to get to them you'd have to be able to drive. But there's no culture of young driving there. In the USA in some states you can drive at 14! In the UK you can't even start learning until 16 and in most of Europe the minimum driving age is 18.
That said, I don't think there's anything particularly strange/hilarious about people congregating in spaces built for congregation or feeling nostalgia for those spaces and experiences as they've begun to fade away. Memories can be made anywhere, and not everyone has access to the green spaces that you and I did as children.
You are right about that, and I admit I didn't thought of that perspective when I was writing my comment. The reason it evokes those feeling of me, is my immediate view of malls as purely consumer space, where everything is aimed at you to spend your money and this is their primary function. My knowledge of malls is limited either to their depiction in movies or experience of shopping malls in my country, where they are probably a bit different and not the most pleasant hanging out space I could imagine. But again, you are completely right about that and thanks for pointing that out!