It is getting tough these days to decipher intentions of those who wish to combat racism with racism, however was definitely not the intention of OP.

One could start a business with their family, friends (who are likely to be the same race), or even other interested people in their community. Finding good founders is quite hard, to narrow it by race is even harder, but that shouldn't discourage underrepresented people who share similar values to organize.

Thank you! What are these people smoking?

Fight (assumed) racism! With (actual) racism!

If by "racism", you mean making decisions based on race only in a literal, overt sense, then sure. If by "racism" you mean structural, large-scale, societal oppression of disadvantaged groups, then no, that's not something a lone startup, or even a bunch of startups, can replicate. The latter is typically what people actually mean.

The over-arching problem is that structural racism is subtle. It doesn't come from managers saying that don't want any [insert racial slur]s on their team. It comes from people making connections through their kids' schools in mostly-white neighborhoods, or getting along because they like the same music or share the same hobby. People like people who seem familiar, and it's harder from someone with a different cultural background to break through. And this is before we factor in the fact disadvantaged groups tend to grow up with fewer opportunities.

Being "neutral" isn't a solution. If you don't try to actively correct for these things, you just end up favoring the status quo. It's not avoiding a choice. It's just choosing the path of least resistance.