Fell into the trap of Assuming People On The Internet Are Like You, yesterday. Said a bunch of things, things I meant wholeheartedly and positively, and (I now realize) didn't stop to consider that I might not have all the information about the situation. Realized, after the fact and after a hint the size of a large brick thrown at my head, what had happened.
Apologized as best I was able, but realized also that 'I didn't know' is only a partially effective excuse, if even that. It really is a two-part explanation, to wit: "I didn't know and I didn't stop to think that it was a possibility." While I couldn't really have tried to find out, because trying to find out is nosy, the very fact I didn't should have tipped me to think 'mmmmmaybe' and moderated my approach.
But it didn't.
Anyway, this is what happens in this age of instant and entirely context-free communication. Back in the day (hahaha I'm old) there were certain assumptions you could make about people just based on the fact that they were on this Internet thing with you. I'm realizing that yes, the world has turned and that's no longer true, and I need to stop acting like it is.