The only people who would take offense at being excluded from off-colour humour are those people privileged enough not to deal with it very often, i.e. it's a non-issue.
Not at all. Consider an analogous situation: While it's not as common today as it was, say, 20-40 years ago, there are women who take great offense if a man opens, or even holds, a door for them, reading into it an implied sexist slight, and responding (either vocally or with body language) in the vein of "I'm not helpless; I can open my own damn door." I open or hold doors for anybody, if it's convenient to do so, and appreciate it when others do the same for me.
Or a bit closer to home: when I expressed surprise at Kirsten Beyer's rather salty nickname, and shock that it was evidently self-chosen, she took great offense at my shock, apparently thinking that I was shocked that
a woman would embrace an "anatomically unlikely" nickname. I was in fact shocked that
a writer, by definition
a highly literate person, (other than, say, Norman Mailer, or some individual whose name escapes me, whom David Gerrold once described as having "taught Norman Mailer how to cuss"), would embrace such a nickname.
And then, of course, there are ST sentient cultures who find common courtesy to be deeply offensive.
The point is, I have met people, of both genders, who consider off-color jokes deeply offensive, others (again of both genders) who enjoy off-color humor, and still others who take offense at the notion that they would need to be "protected" from off-color humor.
And of course, the key word is
humor. If there's no actual humor involved, just profanity for the sake of profanity, that's an entirely different matter. Off-color humor without the humor is simply off-color.
And please don't be sorry for mentioning Keillor. That was actually the first I'd heard of his situation, since about the only nationally-distrbuted programs KUSC still buys is
From The Top.