It’s like saying ”I support worker’s rights.” There is in general a huge power imbalance between the employer and the employee, and a union does a bit to rectify that.

Yeah, if we had a country that was run by Unions, rather than Corporations so that abuses of power by those that ran the Unions was a big deal, I'd have a different opinion. But right now, I'm pretty happy to blindly back Unions, because they've been completely gutted.