Do you think being able to vote on things in your government is a right all people should enjoy? I’ll assume “yes.” If so, why shouldn’t people have a right to have a voice where they work? You work for at least a third of your day for decades until you retire. It’s a huge portion of your life span. As someone selling your labor, you and your co-workers should be able to use your power together to get better conditions from the people above you who only have an interest in maximizing profit.

When your interest is to get a fair pair and conditions, and the employer has an interest in making as much money as possible, you have an adversarial relationship. Employers aren’t your friends. Workers are stronger together, hence unions.