I think you’re missing the point #1 reason people talk negatively about unions, they cost shareholders and management money.
Essentially every large company and wealthy individual has a vested interest in reducing union power or preventing their formation, which results in a vast amount of anti union activity.
That I agree with. Rich people hate unions. But their reasoning is shit. They're only of consequence because they lobby hard against unions. The reasons I listed, however, are more valid (imo) and should be addressed. Addressing them would do a lot to diminish anti-union talking points.