I thought it was basically Hassleback's way of getting at the ballcarrier when, according to rule, he should have to get to the blocker. Clipping is a safety rule, so it would seem to me that that overrides the tackle.
maybe.
I kinda thought he was in the act of tackling the returner, so any other contact is not important....
It was called an illegal block below the waist because if you look at the replay Hasselbeck made contact with a blocker during his tackle attempt at Taylor. When Hartings was nailed for IBBW in the Indy game the same thing happened. Hartings took out the guy with the ball but he also made contact with a blocker trailing the play (and he dove low just like Hasselbeck). So again, technically the call was correct. People just hear some knucklehead commentator spout off on TV and assume they know what they are talking about.
And I might add what did Cowher say about the refs call against Hartings after the Indy game? He came out after the game and said the refs made the right call.