I don`t really believe anyone really needs to drink to have fun. I never have. But some people do think that they do...
Everybody needs to do SOMETHING to have fun, unless doing absolutely nothing is fun. People watch bad movies to have fun. People go to concerts to have fun. People go skiing for fun. There are lots of activities people do for fun. Alchohol is just one of many things one can do for fun or to enhance it.
Take Irish music sessions, for example. Drinking is just a part of the experience, but it is far from being needed. When I play, sometimes I don't drink at all, sometimes I'll nurse a pint, sometimes I'll have two or three, and only once have I ever gotten rip-roaring drunk and I didn't enjoy playing by that point and I may as well have stayed home. When I play there are anywhere between 3 to 10 others, some of them drinking, some not. Nobody cares and most of the time nobody is a detriment to the session because of having a few pints. For any individual, drinking is just something you either do or you don't and it's not stressed, but it's almost guaranteed that at least one or two will be drinking at least a pint or two. I would enjoy the experience whether I drank or not, but when I have one or two, the experience is enhanced, I don't care whether one calls that a need or not.