I was at a lecture last week about 9/11 in a venue where people are very civilized, very polite, and very interested in learning. One of the speakers went off into a conspiracy-type rant which included some generalizations about middle-eastern men and a bit of what I consider to be crazy-talk. It made me uncomfortable and I really wanted to stand up and shout Stop spreading hate!
Any thoughts on how to handle this type of thing? Short of disrupting the lecture (a few hundred people) or booing or hissing, what would you do?
Nothing. It's a lecture. The way that works is that the lecturers lecture and people in the audience listen. It's not the job of individual members of the audience to push back against a lecturer's point of view. If it's really offensive, you just get up and leave as non-disruptively as possible and if you feel the need, express your opinion to in a venue where people have shown some indication that they are interested in hearing it.
I agree with Jrr85, but probably because we both have conservative thought processes (note, having a conservative thought process doesn't make you a "conservative", it's just how your mind works).
If you're in a situation with a lecturer expressing an opinion you don't agree with, you have a couple of options.
#1 Say and do nothing and try to understand where they're coming from.
#2 Say and do nothing and ignore them but otherwise be respectful.
#3 Quietly excuse yourself.
Disrupting a lecturer because you find what they're saying as offensive is not acceptable in a normal lecture format (save for a few exceptions such as a call for violence). If you want to question them during Q&A, or if there is a format that allows dialogue, then have at it (to question their judgement, not their motivations).
If you want to write the organization hosting the lecture for a rebuke of their opinions, and/or blog/publish an opinion piece later about what they said and why you found it to be incorrect, that is also acceptable.
When listening to an offensive speaker always remember that they are ultimately not immune to the consequences of their speech. Remember that the respect you're showing to the venue
is respect for the expression of opinion, not respect for the offensive opinion.