If I was going to work and some strangers told me not to because they were on strike, I'd tell them to get lost.
Uber took steps to help their affected drivers, and stated intent to raise the issue at meetings with Trump. They decided not to engage in the strike along with the taxi drivers. Somehow, what looks to me like a tactical disagreement got recast as proof that Uber doesn't care about immigrants.
I don't think anyone can reasonably argue that the current situation is benefiting Uber's shareholders.
The point being that by breaking the strike, Uber made a terrible business decision. They massively underestimated the backlash they would get. Now they have a (yet another) PR nightmare in their hands.
Why can't public interest be aligned with the profit motive more often?
To some extent this is already the case, you don't see Dow Chemical grinding up children and selling them as couch stuffing, although sometimes they're not very far from that mark.
I saw a headline on HN that said "why always outlasts how" and I believe this to be intrinsic. If we should encourage companies to behave in ways more closely aligned with the public interest, fine. Now, how do we do that? So far, it has been done through varying degrees of regulation and the court of public opinion, but those often fail.
To answer your question - "Why can't public interest be aligned with the profit motive more often?" - because we lack a better how for the time being.