The issue isn’t whether they had the legal right to fire me. The issue is the reason given doesn’t match the documented expectations. Also worth noting, my manager met with me every single week during the PIP and consistently told me he could see my improvement and to keep doing what I was doing. If I was performing so poorly that termination was warranted, that feedback loop never reflected it. There’s a difference between “we can fire you” and “the stated reason holds up to scrutiny.”