Your question reads a bit like: Why isn't there only one bar all the people go to get drunk but several? Most cities have more than one bar and everyone has th

Your question reads a bit like: Why isn't there only one bar all the people go to get drunk but several? Most cities have more than one bar and everyone has their favorite, which isn't the same bar for everyone. I guess it's a thousand small things, but mostly how people feel when reading HN compared to Reddit. Different atmosphere for different people.