Do white male twenty somethings generally write about diversity? Every one I've seen who's expressed an opinion asides from 'my opinions don't matter' gets routinely slaughtered regardless of their views.
Non-white people already often feel like they are spoken over.
The world does not suffer for a lack of opinions on anything from white people -- it's fair to say such opinions are even overrepresented in the world of available writing.
If people already well-represented care about diversity, they should help some of the not-well-represented speak up.
So all white men hold the same opinion? Or is there a finite number of opinions capable of being held by white men, and all of them are represented adequately in print?
It's not weird. If we were deciding between green shoes or pink shoes and all we heard were opinions from people who own green shoes, it would be weird. Does that mean all green shoed people think the same? No. But clearly we'd like to hear from everyone to make an informed decision.
Your analogy is a bit flawed as the color of my shoes is something I can chose and change at any point in time.
If I was born with green feet and you were born with pink ones, perhaps my opinions should hold the same weight as the guy born with pink feet. Just because you were born with pink feet doesn't make you any more or less special than me.