ummm not to defend Eric Jensen, but negativity makes positivity possible. if he has opinions on any ten given bands, and every opinion is positive, that kind of makes you wonder what sort of credence you give to those positive opinions. (if he only writes reviews for stuff he likes, it causes the same problem of perception).
so having five negative and five positive opinions of ten bands makes those positive reviews that much more significant.
so in effect, he's selling Kayo Dot out to amplify his praise of the latest Opeth, I guess.