The 60 people who left makes it clear this is not agreed upon. HN has already played out this debate on the original post so I'll save going into it here, but it's disingenuous to say that Russ didn't quit because of race-related policy, whether or not you think the policy is race-related.
That said, putting out that "apolitical stance" in the direct wake of George Floyd/BLM is unavoidably tied. As others have said, timing is key. If they had the policy from day 1, they might have a leg to stand on. It seems likely in context with this article (and frankly, to many before this) that Coinbase's apolitical stance is not a rejection of all politics but a tacit rejection of George Floyd/BLM. No one should be surprised about a diversity problem in such a company.
This "what else can they do?" question stems from a criminal judicial standard of guilt and conviction, but that is not where this discussion exists. To think that Coinbase must be innocent and needs to prove that over many former employees being on the record + clear statistical issues that all align with the narrative the company has set with previous actions shows a central flaw in the tech community's approach to racism and politics.
I realize the question does not direct say that they must be innocent, but the implications and assumptions here are important to note, and certainly lean in that direction.