It wasn’t a no-knock warrant-- the knocking was mentioned in the story.
Some details in the story-- such as they kept the computer “for forensics” and returned it after a year, strike me as particularly convincing.
I think there’s a narrative where this makes sense:
Theft at school. Finger of blame gets pointed to this kid. Policeman confronts kid, who doesn’t own up (because innocent) and given his future activist status, gives policeman some attitude. Policeman threatens to escalate unless kid comes clean, and kid does not. Policeman decides to teach kid a lesson, gets warrant. Ridiculously militarized police serving of warrant, more or less as described. Afterwards, kid’s (well-off, one a lawyer) parents try to intervene, which hardens police response further.