So you are spamming anyone who joins the chatroom.
I'm puzzled how you could even think that assaulting anyone who joins the chatroom could be appropriate. It's bad enough when people do that manually, but automatically‽
Any auto-greet message is spam and that makes the auto-greeting bot a spammer. Banning that bot was appropriate. Letting the bot run was not appropriate.
A bot should never ping a user who didn't opt in.
I've proposed a change to the chat interface that would make this issue moot. If joining a chat room was an affirmative step, rather than the automatic and potentially accidental thing that it is now, I would have no objection to users joining a chat room being greeted. (Not that it would necessarily be a good idea, but it wouldn't be spamming undemanding users.)
