To answer your question, I've been downvoting topics on agora when I think the discussion is premature or maybe even a bit troll-y. Probably yes people who are downvoting are doing so because they don't like the idea and don't want it discussed. FWIW I upvoted this one though.
As written, I'd be against this. Mostly because I don't know what is meant by vulgar or obscene - are we just trying to police swearing? - but also because just policing the tone of posts doesn't generally work to police the spirit of posts. People can make well-meaning points with swear words interspersed, just as people can essentially tell you to go fuck yourself with polite language.