That was his self-expressed motive on Twitter, IIRC. I haven’t seen a description of the “slights.”
I understand that was his perception.
The headline makes it appear there were racial slights.
I would have placed his (qualified) perception inside the body of the report. Placing it in the title like that makes it look like he may have had some (bonified grievance motive) justification.
Perhaps others will disagree.