I see where you’re coming from now. In most English-speaking cultures, it is not conventional to use hand gestures as a substitute for spoken words in a conversation. Breaking social conventions for no apparent reason is at least potentially rude.
You’re translating those conventions directly to chat. Chat is not spoken word, and it is conventional to use emojis, at least the really unambiguous ones, instead of typed words in chat some of the time. People do not usually do this with any rude or insulting intent.
The maintainer’s claim is that it was a small hobby project at the time. If their security record since gaining more users is acceptable, we probably shouldn’t rake them over the coals for leaving an unsafe debugging option turned on at an early stage.