Since you've already accepted and the hotel has already been booked, why not turn this into a learning experience for your kids? This is a great opportunity to show how you can politely disagree with someone without it turning into WW3. I'm not sure how old your kids are, but kids cannot be protected from the ugly realities of the real world forever, and this could actually give the kids some ammunition for when they encounter it on the playground, which they inevitably will. So, the question might be, how do you politely respond when someone uses language you don't agree with? In that situation, I might say, "I have to say that I really don't care for the language you're using, nor the sentiment behind it. Can we shift the conversation away from bashing certain groups?" If they're polite, they'll say yes of course. If not, they'll insist on more ugly talk, and you can say, "Well, then junior and I are going to take a walk and hope that we can turn to other subjects when we return."