BBC's Annapour & Co. had an interview with Salman Rushdie, which included some discussion of freedom of speech. He mentioned the difference between the UK and US, with us being the most protective of speech. He was asked about hurting people's feelings--he quoted Stephen Fry as responding: "tough".
I've a somewhat similar reaction, I think, though I'm prone to wavering on hot issues. When the context of speech is a public forum, "tough" is appropriate, because people have the choice of avoiding or participating in a meeting, watching media program, etc. When the context is a classroom where the participant doesn't have a choice, or has less of choice, ideally I'd want to see advance warning.
Rushdie said there's "no right to not be offended", which I think is correct. There is a right to not be surprised.
There's likely some situations which would undermine my position. How about the advocate who intentionally wants to offend, uses terms or takes positions which be offensive? Consider somebody who advocates for the expulsion of one group in contested areas: whether it's the Middle East or Northern Ireland?
In such cases there's the question of the forum: should the person be denied a particular forum? I think they can be, possibly using an economic analysis: what's the cost of allowing participation and what's the possible benefit to the audience?