Well, I would question the notion (as others have) that union activity is anti-company or company-undermining. The company managers may perceive it that way, but that doesn’t make it the case.
There seems to be an underlying assertion embedded in the question. Namely, that both parties in an adversarial relationship should be treated equally under the law. This ignores power dynamics in favor of philosophical cohesion. Practically, though, we know this results in the exploitation of the individuals with less power. That’s why the NLRB was created, in response to worker exploitation. Indeed, creating a framework to settle disputes between individuals of disparate power is one fundamental reason for the existence of governments, the rule of law; it separates societies from anarchy.
“Fair” does not always mean “equal.” There’s a reason that people who are rich pay more both nominally and by percentage of their earnings.
It’s disappointing that this question continues to be raised. The position that the question implies was refuted almost a century ago, at a time when young men died of typhus from poor living conditions, a time when children regularly worked 12 hour shifts in mines and slaughterhouses. It took a massive movement to convince the lucky few who governed the exploited that human life is worth more than economic value that can be extracted from it. Yet here we are —- people who are not more than three generations away from almost certain exploitation questioning why employees should be allowed to hang posters on the cork board and talk about their own interests on the property of a company founded by a man with a private rocket company.
It’s not that I think it’s a moral imperative that you have solidarity with Amazon workers, or even reflect on your own possible complicity in their exploitation. I doubt a person capable of asking this question is interested in such a reflection. You should, however, come to the table with a modicum of historical understanding.