The CIA has been recruiting top students from liberal universities since its inception (and before). I’m not sure its the kind of thing (Leftism) that can be excised from an institution like the CIA.
Yes, and this is a major, major problem at all levels of federal government. It's quite stupid to limit your talent pool to specific universities, or to universities at all. It selects for elitism, mediocrity, and groupthink.
Agencies like the FBI and CIA should be recruiting, to a large extent, from law enforcement, not from universities.
Further, I don't think these agencies can be trusted to police themselves, ever. There has to be much, much better oversight - and a non-government/civilian component of this oversight. The penalties for abusing power from within an intelligence agency should be similar to the penalties for being a spy. Both are cases of subversion.