By the late 90s, the TV-ification of the Internet was well underway, and I don't think many people even tried USENET to discover if it tasted good, or not. The nice thing about regex-powered killfiling, is you don't have to use regexes, but the power is there if you need it. TBH, I never needed a killfile much, because the audience (of the groups I followed, at least) was better-behaved than a large proportion of the participants on Twitter, Facebook, and Reddit today. And whilst there were certainly capricious USENET mods, they couldn't prevent someone from setting up alt.pizzas.unmoderated or whatever. Reddit's flat hierarchy means people are unlikely to discover better-moderated versions of subreddits that are badly-moderated, but have the "obvious" name.