On a practical level, a union that concentrates just on its members interests, is not able to concentrate on its members interests. Just as one person can be crushed by a company, a union at one company can be crushed by an industry. The UAW organized GM, then Chrysler then Ford (one of the weapon carrying workers in the GM strike was Larry Page's grandfather). This kind of thing is necessary for the survival of one union. If FedEx is not unionized (it is not), that weakens the union at UPS.
The AI researcher said there were racist aspects of Google AI, IIRC. Whatever the specifics of that case, unions do not prosper over the long run with a racial divide. There are numerous cases of jobs traditionally done by black men replaced by white scabs, or vice versa. It is why Bernie Sanders wants less immigration, despite the disapproval of upper middle class liberals to his right - too many unassimilated Latin American workers can be played against native workers in a divide and rule sense.