He has political right to free speech. However, all employers (such as the NFL) regularly limit the speech of employees for the good of the company. His employer can exercise the right to regulate his on field behavior. Limiting end-zone celebrations is one example of regulating players speech.
In normal employment for instance, try disparaging trans-women (or any other minority) in a company e-mail -- and see what happens. You won't make it to the end of the day. When your words are leaked to the public, your company will be harassed and you will be followed to your next job by an army of the offended.
By the rules of your identity politics then,
you have no authority to criticize how white people conduct their business. See how stupid that is? No, you probably don't.
I've been a sissy since 12. I share my university dorm suite with 4 Black men. I cook, clean and keep my Black men
very happy. At my job in the islands, I am still a Black squad girl. Sweetie, I've got more Black DNA pumped into my body than you are made of.
I also interact everyday with masculine Black men, who handle their affairs as men do, and protect me when I need it. They don't cry to a white sissy about how people are mean to them. I care though. If you can't get past this weak mindset, I can help you find some panties, skirts and heels in your size.