He will take the opinion hit, squaregear
Then again, it also allows a little exploit where if you want to piss off a vassal you can add him and drop him over and over from the council. If they made the scores for appointment and removal equal, this exploit would be gone and you could more easily shuffle your cabinet. Probably not a bad idea.
Edit
Corp25: English, Irish, and (I think) Norman count-level titles are called Earls. I'm not really sure why they added this, it is nice flavour but then they should have it for more regions. As far as titles go, there are five cultures in the world: European, Greek, Arabic, Persian, and British Islanders.