You have to know your audience, and that's difficult with someone you're just meeting. We watched the UFC fight at my house last weekend and a guest brought over some friends, including a really big guy who weighed the better part of 300 pounds. My roommate started to go into a rant about Harley riders, but before he said anything too untowards, he had the sense to ask the large man if he happened to be a Harley afficionado. Just common sense; you don't want to risk offending someone who looks like they could snap you in half.
So, if you know someone is gay, and you don't already have a rapport with them, it might be considered unwise to start dropping jokes from Andrew Dice Clay's reject pile on them. They might inadvertently make you look like a bitch, for example, and you don't want that. You'll find that once you get to know someone and build up a sense of friendship or camaraderie, you'll be able to get away with more offensive banter because they'll understand you're not actually a bigot, you're just playing one for the purposes of humor.
Or you might just be a bigot. In which case, you're going to spend a lot of your life with a handprint across your face.
