You must know that the SWAT team didn't know they were part of a hoax. If there actually had been an armed hostage-taker then I doubt that many people would be saying that shooting him with rubber bullets was illegitimate.
Having said that: 15 of the 17 top-level comments on this thread are explicitly critical of the police in this situation, so I don't know how you you're getting the impression that we aren't allowed to hold them accountable.