Although I think the American Civil Liberties Union is incredibly valuable and I'm glad they have a lot more money now to fight for the American people, I'm questioning all of this. Where was the outpouring of funding when black people were being gunned down by cops from West Coast organizations? Where has YCombinator been as our own impoverished African-Americans are getting slaughtered in the streets of Chicago? Wh…
To answer/satisfy your concern/question is impossible without inaction. The cases you mentioned already happened and are in the past. In essence you are proposing that YC does not act to help solve this current issue, because worse issues happened in the past, and YC did not act then, so it does not deserve to act now (at least, without being accused of hypocrisy and selective outrage). This mode of argumentation results in nothing happening to solve the current issue, just by virtue of there existing past worse issues. I don't think you are really in favor of this.
As for the marketing argument, sure, I can agree this playing a minor role in this decision. But not a major one. There is not much evidence I am aware of, or that you pointed out, signaling that YC does not act in good faith. Though absence of evidence, is not evidence of absence, this alone is not a solid basis for posing that any action that YC takes is purely profit/PR-driven.
Likely, this decision was not instigated out of marketing motives, but like any good decision for a for-profit company: it aligns with marketing motives.
Another angle to look at motives for problem solving: Is the crime of having a less than glamorous motive worse than the outcome of solving the problem? Donating to non-profits makes me feel good. Is this egocentrism worse enough to stop donating?