回复：该不该签这个协议？

I would sign the agreement.

Employments are largely at will. A company can fire an employee for good cause, for no cause, or even for bad cause. Unless you were under duress or retaliation. For example, courts held companies liable when an employee reported illegal accounting activity to public officials, or an employee refused to do a job violating public policy.

Geneally courts are reluctant to intervene employment situations for reasons that companies have to have their own freedom to operate.

Take it this way, it is their loss. Take the money and move on. Good luck.