From reading the story and gleaning what information was there, I can only assume, this was just a random attack by three teenagers, bored by the lack of soda shops in the area. or something.
Nothing racial here. Just youngsters feeling their oats.
No one except a racist would even think otherwise.
Maybe those evil racist should be sent to a re-education center and the city should build Soda Shoppes for teenagers. That would eliminate this sort of thing from happening.
Paging Winston Smith.
Not if they were in fact part of the MS-13 gang. Like you I could possibly assume this might have been a rite of passage or some other nonsense to gain street cred with the gang.