I have a differing view. Yes, there are ways employed at will policy proects employers, and yes, it can be abused.
But here are all the ways it protects me as an employee:

I can leave at any time. Yes, 2 weeks notice is the standard courtesy, but that's all it is. I can leave at any time and face no legal repircussions.
If I'm fired for no reason, i can collect unemployment benefits while i look for a new job.
If I'm fired for no reason, i can state this in my defense at job interviews. "I was given no reason ma'am. I would have welcomed the opportunity to improve my performance, or address the issue. Perhaps it was a financial issue within the company. I simply don't know."

Losing a job is devastating- i really do understand this. Ive been on the receiving end of this bad news before. But i prefer it to working under obligatory contract, which i feel pavez the way for worse abuse.
Just my opinion.