Earlier quoted context omitted.
Leverage. Without a union, you can ask management for stuff, but they can just say no. Your only recourse then is to quit, which wouldn't change anything when it's just one person. With a union, a work stoppage is a possibility. Suddenly management have a reason to come to the negotiation table and make concessions.
First of all "asking for stuff" implies a negotiation between two parties. A negotiation implies that either party can walk away from a deal. You're implying management shouldn't be able to say no. Management is not necessarily out to get employees and excessive compensation or regulation around hiring and firing leads to either insolvency or stagnation. It's a balancing act. A union can be just as exploitative as a…
A corporation is not entitled to anyone's labor.