You're the one making the claim, Tom...
>As for the editorial pages and the rest, you can do your own research.
Since you're making a claim that certainly isn't obvious or common knowledge, I'd say it's up to you to provide some evidence.
I read quite a number of the prominent liberal blogs and I don't recall any asserting that it was unrelated to the impending election. Even among the hoi polloi at DailyKos, I don't recall disagreement on that.
Plenty of disagreement over other aspects of the bombing, but unless I missed a lot of articles (not counting a poster or two here at HZ) you really are setting up a straw man here.