Yes, after the cops came with a no-knock warrant to the wrong house with the person they were looking for already under custody and they didn’t identify themselves. The cops never should have been there in the first place (at least for the reason the warrant was granted) and did nothing to distinguish themselves from a burglar who was breaking into the house.
You're right. Instead of just yelling "Police!" they they should have announced "We really really are the police - NOT BURGLARS - and we're coming in! Please don't shoot."