My gut reaction would be “actions still have consequences motherfucker”, but my gut would also be to immediately remove this person from ever interacting with me again.

Sometimes, the results of something you do don’t quite match your intentions. Mistakes happen, miscommunications happen. A genuine person would respond “oh fuck, that is NOT how I meant that”, and apologize. A gaslighter does the above.

That’s an awful lot of words to say it’s a backdoor that could, plausibly, have been installed unintentionally, but is still very much a backdoor.