Uber has turned off surge pricing in the past during unexpected events (such as the New York bombing), so as to not be seen as profiting off unfortunate events.
This seems to have been done under the same principles.
(Whether one agrees with the policy is not too relevant. The subject of price increases during disasters has always been a controversial one, even before Uber, and that's a debate for game theorists and ethicists.)
Regardless of which choice Uber makes, they are open to criticism. There could have been articles right now about how Uber is profiting because of the strike by raising rates.
All I'm pointing out is that their action is consistent with how they've handled previous unexpected surges which had potential for bad PR.
To be clear, Uber broke a strike in support of the immigrants and refugees, advertising that they were doing so. Taxis drivers stood in solidarity with the immigrants and refugees by halting service in and out of JFK. Uber sent drivers there. Surge pricing was just an implementation detail of their being scabs.
If you want to argue on behalf of Uber breaking this strike, please, go ahead.