Hmmm - not sure that 'biggest' is the reason. I have a feeling many countries object to the arbitrary way the US steps in (read 'invades') some countries but not others, and the strange coincidence between oil dollars and the overlooking of human rights atrocities (eg Saudi Arabia)

And then there are funamentalist non-christians who just object to the fact that the US seems to be run by fundamentalist christians.

(in that paper I was amused by the views of Canada - the only western nation which didn't see the US as honest!)