Checkmite
Skepticifimisticalationist
The article is clear that the alleged hat was worn previously, not at the time of the beat down, and that the mother alleges that her son was bullied in an ongoing way since then. Why note that you don't see a hat that is not claimed to be there?
I'm seeking something to establish a causative link.
If the claim is that a man harassing a black person is doing it because he's racist, a police officer seeing that man repeatedly shouting "[f-word] that [n-word]!" on a street corner immediately afterwards is a strong indication that the man is racist, for instance. A restaurant cashier telling people of one race they must buy something first before they're allowed to use the restroom and then telling other people of a different race that they can go ahead and use the restroom before buying anything, is strongly suggestive of the cashier making an exception for racial reasons, so that allegation has merit.
Saying that a fight on a bus happened because the victim wore a Trump hat a few days earlier, when the hat is not present and none of the assailants seems to be shouting anything about a hat, or Trump, is not as well-supported.