I wouldn't argue with the dude; he's got a clear case of bad-faith-itis. What you did was bad, so you shouldn't have done it, but no I won't tell you how to fix it.

The absolute best you could have done is cross-posted to a Mastodon/Bluesky/whatever account as well, but you can't just always go around yanking the rug out underneath communities especially if you're in a position where it's not just lazy shitposting and worthless commentary.

...that said, you have moved anything you can to being posted somewhere in tandem riiiiiiight?