I saw a keeper who had a €10M balance in his bank account get a 7.1 while another guy with €1.2K got 8.0. I guess he had his money invested or something.
More seriously and out of linguistic jokes, yeah, ratings are harsh on goalkeepers. I've seen some get high ratings, but it's very rare. I have the feeling like passing completion and other such stats count too much or difficult saves too little.
Though what annoys me is how hard it is when players make mistakes leading to goal... against the players that had nothing to do in the play.