A well-researched, thoughtful response can demonstrate that someone is a propagandist or lacks integrity. No need exists for profanity.
Yes it can, provided the audience is highly intelligent, objective and decently educated. So what do we do about the other 90% of the public?
Profanity they understand. It gets the point across without having all the complicated thinking necessary to prove it.
Trump instinctively understands something that a lot of intellectuals do not understand. Politics is really just a game of "the Dozens." It's about who can establish Alpha dog supremacy and not much else.