You mean the Steelers aren't allowed to tackle below the waist previously? So you're saying that since there have been bad ref calls in the past the refs should job the Seahawks in the Super bowl?
It's not tackling below the waste, the call is an illegal block below the waste, the problem is on the play here and the two where the Steelers got nailed the "block" was because the would be tackler (after an interception in all three cases) needed to get through somebody to make the tackle, and because they hit that somebody low they called it a personal foul low block. I disagree with the concept of call but at least they're applying it now exactly the same way they applied it in the regular season.