Freshers weeks for all UK universities are like that. And most teenagers are fine with that, rich or poor. It's an easy ice breaker.
I don't know how you managed to miss this during your university career, but there are absolutely tons of clubs in every university. Sports, political, hobbies, music, etc. Nothing to do with drinking, apart from maybe a once or twice yearly optional social night.
There are 400 clubs registered at the OU student's union:
Clubs and societies tend to be too... organized, specific, serious? If you are Feynman, do you join the bongo drum society? I mean you play them, but you're just having fun, joining a society for bongo drum players seems like an overkill. Do you join the lockpicking society? If you enjoy playing backgammon every now and then, do you join the backgammon society? If you are interested in hacking software for fun, do you join a competitive computer security club?
After all, you are not interested in these things narrowly and specifically. You just would like to hang out with like-minded people that like to have fun in these sorts of ways.
In these societies, you mostly end up with some specific 'serious' activities (e.g. a talk, a lecture, a discussion, or something competitive). And social engagement then happens separately, usually at a social in a pub, also as a 'targeted' activity. It is a good way to get more serious about your interests, but does not seem like a natural way to make friends.
I don't know how you managed to miss this during your university career, but there are absolutely tons of clubs in every university. Sports, political, hobbies, music, etc. Nothing to do with drinking, apart from maybe a once or twice yearly optional social night.
There are 400 clubs registered at the OU student's union:
https://www.ox.ac.uk/students/life/clubs
Including compsoc, which would have been a way to meet your fellow CS grads:
https://ox.compsoc.net/
And a competitive computer security club:
https://www.ox002147.com/
And they're just the ones I found by searching computer.
You could've packed your calender with different activities meeting new people every night and never have felt the need to drink a single drop.