you start posting in a group tagged with a certain state, that gives them a clue. Maybe you use your username elsewhere on other sites? Maybe you posted on sunday gunday and exposed a serial number or what you thought was an innocuous picture of the back of your car with a Trump bumper sticker. Every bit of information helps the skilled doxxer.

If nothing else you then give them a state to file a complaint against you.

I already know you and your dad fly the american flag outside your house, and you are registered as an independent. Not huge info to discern, but all the clues eventually add up.

you start posting in a group tagged with a certain state, that gives them a clue. Maybe you use your username elsewhere on other sites? Maybe you posted on sunday gunday and exposed a serial number or what you thought was an innocuous picture of the back of your car with a Trump bumper sticker. Every bit of information helps the skilled doxxer.

If nothing else you then give them a state to file a complaint against you.