What kind of culpability did you want Ben to show you? He already said that he understands you felt dismissed, unseen and misunderstood by what he said and he apologised for that. What more did you want? I'm genuinely curious what this additional "taking accountability" would have looked like in this particular situation?

Or is it just that he said "I'm not perfect" and that was it for you?

I'm just a bit confused here. It's your right to leave the group for any reason. I'm just wondering what exactly was lacking from his apology cause from the way I read it, it sounds like he understood what he did wrong in invalidating your feelings, and he apologised.