Outwardly, I have no problem with STs having characters, nor do I have a problem with our STs having their characters. I do remember that the question of whether or not the players were ok with Brody and Taweret joining our game was asked and there were no public objections. Safeguards would be put in place and there would be no issues... End of story.
Perhaps, if anything those safeguards could be refined or better communicated so none of the players would fear any funny business. Maybe even partnering with an ST or STs from one or more other games that we are close to and frieldly with, to offer a vote, opinion, or governance in matters related to any controversial ST PC activity. I'm sure there is a way to allow everyone, including the STs, have fun with their own characters.