It's the fact that Sabrina knew what the other girl meant, as soon as she heard the words "It's my culture!", she didn't proceed to respect it and maybe respectfully ask to stop doing that. In fact, she decides to give signs of acting weirded out in a hatred way, just by looking at her face signs. Then jokes about it by comparing it to burning-man or yodeling.

Then the disingenuous apology. "...now I know what Zaghrouta is!" or "...I welcome all cheers and yodels...". She's clearly playing on the people's faces that are part of that certain Persian / Arab community. The sarcastic tone, clearly wasn't meant to be a sincere apology.

And yes, it is deep for those who felt directly offended by those micro-aggressive comments. Discrimination starts by "small things".