It's undesirable because the company shouldn't be forced to allow unions. Maybe the company thinks unions are inefficient or doesn't like the collective bargai

It's undesirable because the company shouldn't be forced to allow unions. Maybe the company thinks unions are inefficient or doesn't like the collective bargaining power (in extreme cases it resembles a monopoly). Companies and workers are entitled to their opinion. Workers can choose to work at companies that allow unions. Of course management (multiple people) should be more powerful than an individual worker.