The judge the FBI went to not only has made social media posts trashing President Trump, but judge Bruce E. Reinhart, was a prosecutor against Jeffery Epstein, who it seems suddenly came into some money to start a criminal defense law firm and within days of quitting the prosecution team his first client was the infamous child sex trafficker Jeffery Epstein. Reinhart directly represented Epstein’s top co-criminals including his pilots.
There is a talking point going around that Reinhart is a “Trump appointed judge.” Newsweek reports that Reinhart, as a magistrate, is such a low level judge that his appointment was handled by underlings and that President Trump likely never heard of him. Robert Barnes reported that most of Trump’s lower judicial appointments were picked by Senator Mitch McConnell. Magistrates do not go through Senate confirmation, they are appointed by the district judge to act as “judge helpers.”
Political Arena 
Greg Jarrett explains what low ranking judges such as a magistrate do. There is a reason the FBI picked this guy.