These scores aren't a surprise to anyone who managed to play the demo.
The first thing I said when I finished all 3 campaigns in the demo was, "RE6 is going to be very polarizing." There were parts of the demo that I found entertaining, yet I can't blame people for being critical of RE6, even if it was clear for months that this was the direction that was being taken.
The wide range of resulting reviews are exceeding the extent of my expectation of how polarizing it would be, but the split of opinions itself doesn't surprise me at all.