That does not make it legal and it does not eliminate the responsibility of asking for the warrant and using it.

Not saying there was a conspiracy here, but bad judges exist and arranging for a warrant is possible even for honest judges. If you are a policeman and you want to kill someone, get a judge to sign a "no knock" warrant, get in their house and shoot them, it happened many times; there were cases when the warrant was not even for the address of the poor guy that was killed and last year the warrant was for someone that borrowed a lawn mower from the judge who signed it and did not return it. So the warrant excuse is not so good.