I kept my mouth shut this whole time because I think this thread is pointless but I feel I have to say something now.
Nobody here knows anything. Everything you are saying is pure speculation based on circumstantial evidence. And even if you do have solid proof that someone is being Mechallel Shabbos, this thread will do nothing to help/stop him/her.
You don’t know the background of the poster you all think is being Mechallel Shabbos. You don’t know whether he/she is Jewish, frum, or a tinok shenishba. This thread is pointless as we don’t know all the information.
So stop playing detective and move on.