"an informant apparently testified to this and a judge approved it" sounds very far away from what I understand "swatting" to mean normally.
Swatting is the action or practice of making a hoax call in an attempt to bring about the dispatch of a large number of armed police officers to a particular address"
Either there was an informant, and the false claim was made to a police officer, or there was not informant, and the cop made a false claim to the judge. Either way, the intent was to get cops to show up and screw with Afroman, and that goal was achieved.