So, here's my take on why
@CaptainAmerica felt as he did...
There have been many times where singers of color have sung the national anthem with their own embellishments. Those embellishments are not appreciated by some people of different backgrounds. This version, had a similar soulful embellishment. And I believe it was done on purpose (not a bad thing, but it's not by accident).
So, for you to say that "he can't handle the seasoning," could mean that has a bias against embellishment by a woman of color.