Disengage should only be enforceable if it’s invoked in good faith. Posting a wall of text and using it to get the last word forfeits any protection it provides. It’s the equivalent of calling for a fair catch in American football, then attempting a return.

Immediate edit: it doesn’t even have to be a wall of text. Any response included with the disengage request invites further discussion and suggests that there is a desire to continue the conversation, at least to the extent of having the final say.