The swear filter used to contain 'normal' swear words in its beginning, however certain people have apparently made it a sport to use different words (language/slang evolution kind of stuff), so even simple and innocent words can be an insult if used in a specific context/community. Thats why the swear filter got more and more seemingly unrelated words added to it.
Solution? Fix people, make them less dumb and instead act nice to each other and we wouldnt even need that filter in the first place. As long as people search for ways to be mean to each other, we have to search for ways to stop this from happening.