1) converts aren’t obligated to reveal that they converted and asking them is against halacha (only in specific situations is this info necessary. guarantee seeing someone posting on tumblr or at shul is not one of them)
2) if you find out someone is a convert, you should act like you don’t know/treat them the same as you would every other jew (because that’s what they are)
3) if you do know someone is a convert: don’t ask them how, where, when, why they converted because it’s against halacha
4) don’t reveal someone’s convert status to others; it is against halacha
and i really can’t believe i have to write this, but:
5) converts who have gone through the conversion process aren’t goyim.
eta: also questioning someone on their jewishness is just plain rude