There’s no scenario where you’re not the a-hole if you’re going to parrot something someone else told you in private, elsewhere.

I can think of several, including the one being described in the original post

Seems like the finger should be pointed at you for being so naive and trusting someone so blindly?

And reading the post, you telling me if OP was sending nudes of his girlfriend to a group chat, Derrick is the asshole here?

Yeah alright.

I meant that the guys in the chat were scum for for sharing their SO dms with each other.

This is an over generalization. How can you support that this is true other than for yourself alone?

Sometimes the unfiltered things I discuss in private are for the purpose of getting feedback. A brainstorming space without any of the regular inhibitions censoring free thought. I’m not looking for affirmation, but genuinely want to see what the unfiltered feedback would be, and am ready to change my option on a dime.

Take this to the next level: you do this in your own mind / imagination before you speak. You think things that you don’t say. So is everything in your mind, even things you think are wrong and choose not to express, your true self? And you should be ashamed of shameful thoughts?

Also what do you even mean by “true” self? If I act differently around different groups of people, which one is true?

This is a terrible take. Obviously, I can say something offensive to a friend that they would find funny exactly because they know I don't mean it seriously.

Saying that is some kind of "reflection of my true self" is honestly just dumb. I'm saying the offensive thing because I find it offensive myself, and because I would never say it to someone I don't trust to understand that.