Your entire argument that she 'just isn't being nice enough' is fucking weak. She's saying white men don't get the final word on shit not intended to speak to them. Any reasonable person among white male critics would get out the fucking way and acknowledge shit ain't about them all the time.
What world do you live in where multiple voices cant be heard about the same thing. Or that the skin color or gender of a protagonist automatically makes the movie "about" that category of person.
People can criticize movies, their ethnicity and gender does not matter. One person speaking their mind on something doesnt overwrite or block out another persons voice so there is no reason to "step aside".
You as a listener are absolutely in your right to listen to and ignore any and all those opinions based on whatever criteria you so choose. But I wouldnt expect a cis male to feel compelled not to give his opinion on wonder woman or captain marvel (which at their core are just more super hero movies and can be criticised as such regardless of the identity of the protagonist) any more than I would think an african american couldnt form a valid opinion on movies like superbad or anchorman.
Absolutely there should be more diversity in film reviews, but that can be done with the addition of critics from different backgrounds and doesnt require silencing others.