We can't end this debate without the warrant. You can acknowledge that you don't have that information and there's a chance it was justified before they rolled up if any of the people were known to be affiliated with dangerous people. If you know of a way to figure out if every situation is going to be dangerous before it happens, definitely put that forward. I'll acknowledge that it could have been some bored SWAT guys just looking to show off and it was completely unnecessary show of force and waste of taxpayer money.
Justified? No. I agree there's a chance—a very very slim one—that they had information that would make me think their show of force was reasonable. But AFAIK, they didn't supply it. They didn't justify their actions to the general public or to any oversight agency, either ahead of time (understandable) or after the fact (less so), and nothing compels them to do so. They can execute the warrants as they see fit, using basically whatever ex-military hardware they like, without explaining themselves to anyone.
I further believe that this lack of justification is routine. Even if there was a good reason, that do this routinely without being either compelled or persuaded to supply it is by itself evidence our police are militarized.
American police collectively lost a lot of trust and authority. Obviously the most significant aspect is actually murdering people like George Floyd in plain sight while wearing a badge. But dangerous stunts like this are a contributor as well. Do they want to regain our trust?
I'm trying to figure out what kind of warrant you're imagining that would justify bringing a full SWAT team to evict squatters who were known protesters in an ongoing legal dispute with the property owner, not some gang kids.
