There.

I did it.

I stood up for myself, my friends, and for what I knew you used to be.

I'm sorry it had to be over a stupid thing, but it was a "last straw" kind of thing.
Do I regret it? No.
Even a little? No. Maybe a little, but someone had to stand up to you.

I am not going to say sorry for something I did not do.
No matter how much you want me to say it.