[RCW]

I think the reason people were surprised is given in the polls on this site (and others).
Ulrika was very high in the "person I most dislike" which meant there was a lot of critical comment about her on boards, in the press and elsewhere.
She was also high in the "favourite to win" polls and so received a lot of votes.
To put it simply, Ulrika really divided opinion and there were few neutrals.