He didn't say "Girardi sucks". He just said the Rangers shouldn't build around him.
Which isn't a terrible opinion at all. Girardi is good player and a warrior, but he's a noticeably flawed player. He's prone to turnovers and is a terrible puck mover. He's going to want 5M+ as a UFA, and frankly, he's not worth that much. Aside from last year, he has been a #3 caliber defenseman. We already have Del Zotto, McDonagh, and Staal, who also needs to be re-signed the year after Girardi is a UFA. Staal is better than Girardi, and younger, so he should be more of a priority.
I'd definitely shop Girardi at the draft if I were the Rangers. Try and get a young centerman from a team looking for a defenseman. Problem is, not many teams have expendable centers. Maybe to Edmonton for one of Yakupov or Gagner. Doubt we could get Yakupov, though.