You don’t tolerate people watching porn near you. You don’t have to set an age. You just say, “if you’re going to look at stuff like that, get it out of here.” If they won’t, you don’t argue. You simply say, “OK, then, if it isn’t going, then I guess it is up to me to go.” Then you leave. You can let them know you find it offensive, and you don’t care if they think you are a prude or a nutcase for thinking so. If that makes you crazy, you’ll have some very good company in your asylum in that case, wouldn’t you?
You don’t apologize for asking someone not to take the Lord’s name in vain in front of you. If he gets angry at that, you can say, “hey, I can’t stop what you do. I let you know I didn’t like it, on the off chance that you happened to care whether I was comfortable around you or not. If you don’t care, then yes, it is up to me to either get used to it or take myself elsewhere. You might ask yourself why you are so defensive about acting in a way that is comfortable to you in your own home, but that’s on your plate.” You may learn it is a pointless thing to do, but don’t apologize for ever saying anything.
When you were condemned for “inciting such anger,” I think a bewildered look would be in order. “Most people I know would have either apologized for an unintended offense or else calmly told me that while they regretted that the speech made me uncomfortable it would be up to me to decide how to cope with the fact that it would not be changing. Period. It is called communication. Not that hard. Why he decided to go ballistic, I have no idea. Believe me, if I knew which red button I’d pushed and where it was, I wouldn’t push it again.” Otherwise, take the Little Flower route and do the spiritual work of mercy of “bearing wrongs patiently.” Do not apologize for taking the commandments of God seriously, however. Either tell the truth or else remain quiet.
He is what he is: the kind of host that he is, the kind of parent that he is, the kind of friend that he is. Either get used to getting up and leaving when the situation is such that you can’t endure it or else stick around to endure it in person. You’ve tried communication. File that under “tossing pearls before swine.” Quiet endurance, always avoiding any self-aggrandizing appearance of martyrdom, and a silent prayer for those poor souls is probably the best route. You never know what good that might do.