Or maybe it's getting downvoted because it's trying to counter an argument about diversity of past life experiences with an argument about diversity of class membership, which is quite reductionist.

Class membership can be useful as a proxy for e.g. power structures, but if you're already looking at investors, the most important factor influencing power structures is that they have a lot of money. Maybe there are differences in the ways white and black people with lots of money abuse their power, but that'd surprise me.