For GS. Maybe. Then rinse and repeat for other companies that pull the same thing in the future.
Plus a private email does nothing for the little guys that have no clout, who would be completely ignored if they made the same complaints. 37s helped far more people than themselves by doing this.
The latter however is a separate (and valid) point. I'm not against them being pressured; I think that was the right thing to do and I'd not have backed down until they made the change more generally, but I think that could have been done just as quickly and easily (with this specific company, not some other one that we're not talking about) in private.
I'm a founder too, so I'm mostly imagining myself in their shoes and how angry I'd be if somebody took a very public swing at my company without giving me a chance to make it right. I'm sure the 37s guys are as protective of "their baby". ;-)
Plus a private email does nothing for the little guys that have no clout, who would be completely ignored if they made the same complaints. 37s helped far more people than themselves by doing this.