I’m not sure I’m hearing anyone saying diversity is a bad thing.

People used “diversity hire” as an attack on Harris, but no one is using it as an attack on Walz, even though everyone basically immediately knew that the VP pick was going to be an older white man if only to make the ticket less of a “leap”.

That an all woman ticket, a ticket with two not-white people, or anything else not “default American politician” would face issue is kinda OPs point that we still have a long way to go to overcome those institutional barriers you mention.

Needing to consider diversity or representation when picking people is a sign that something has already gone wrong.
If the system were just and those barriers didn’t exist, people wouldn’t consider diversity, they’d just pick the best person and the diversity would just be there as consequence of demographics. (In a fair system, the top N% of the population will have a comparable demographic breakdown to the population at large).

It’s a sign of a cultural hangup that we definitely consider diversity, and need to in order to have decent representation, when making these choices, and even more sad that it’s only used as a cudgel against minorities , even when they were the first pick and others are being used to offset their “riskiness”.