Trying to debate relative and humane decency during a show here is like trying to convince a Disney fan that The Seas' overhaul was unnecessary and did more damage than good.
Simply put, it's unwise to try and say otherwise because you've never truly been offended at a Bill and Ted show before, and I've gone to each for the past three years. If your advice is to go in with a more open mind or to numb down how things make you feel or even just to not go, you're simply missing the point because it's not you or your kin who's being targeted at these shows.
Like I said, I can take jokes. Unnecessary ridiculing based on stereotypes and minorities just leave me with a blank face until something else comes in that's mildly amusing. Also like I said, there is a fine line. Crossing it simply loses parts of your audience.