The doctor who flipped off Russell Westbrook places the blame on Westbrook for calling him fat.  He did so in his sort of apology, Philly Voice:

"As a part-time comedian I realize that my words and actions are sometimes inappropriate," Harkaway said in a statement to Philly.com issued by a personal representative. "In this instance, after standing up to boo and being provoked by Russell Westbrook calling attention to my being overweight, my action in response was clearly inexcusable and I am embarrassed. I sincerely apologize to my fellow Sixers fans, the Sixers organization, my colleagues and patients, and to Mr. Westbrook for my behavior."

This is the perfect apology, if you do anything over the top, possibly inappropriate or racist add into the apology that you're a comedian.  His double middle fingers is part of his comedy routine.

Apology accepted doc.  But what do I tell my small child who might have seen a fat white man flipping off and screaming at an incredibly fit black man?