What does it mean for something to be offensive or unacceptable? Just because something someone says causes you to respond emotionally doesn't mean that you can make the judgement that it is objectively wrong (or right). I've seen a few posts on reddit in regards to this, and, in my opinion, it comes down to this:
When you say something offends you, you are openly claiming that you have no control over your emotions. You can't control yourself, so you need other people to do it for you.
It's your opinion that it's not acceptable. Nothing more.
When it really comes down to it, the only way anyone can ever be "right" is because they have the 'bigger stick'. Are you just going to sit there and think you're right by virtue of your perfect sense of morality, or are you going to embrace some humility?