Many companies regularly work within mainstream political action such as LGTBQ+ rights, data privacy, homelessness, local housing or public works, and children's orgs such as Big Brother Big Sister. While these vary in controversiality, relevancy, and apolitical nature, it's not at all uncommon to see companies working in these areas (and others unlisted). Often companies grow into them along with size and profits, so I don't know if Coinbase historically can be taken as sign of consistency either. What Coinbase did was effectively say "well now that BLM has entered mainstream politics and other companies are taking stances, we no longer feel that the mainstream politics of the industry are agreeable to us."
The George Floyd spark very much "outed" Coinbase here, because it became an issue you couldn't avoid taking a side on. That's just the state of the world and you're right that they couldn't have anticipated it, but they chose to make a clear stance rather than trying to ride the thin line, and they became less diverse for it. I don't know why anyone would be surprised their prior actions match that recent stance.
Again, I'm trying to avoid the philosophical "Should companies be political" debate that's already been hashed, but simply stating how their actions translate in the current landscape.
