Why would they not inform me about my poor performance earlier? Why would my team lead repeatedly lie to me?
tl;dr: They probably didn't fire you for poor performance, but for another reason that they don't want to share. Let it go.
You didn't say what country you're from, but if available, file for Unemployment ASAP--it is your right. In the States, if ...
Legal reasons, maybe?
If you fire somebody for a very specific reason, they can take it to court. Normally, companies avoid going to not lose money. Firing somebody because of "poor performance" seems vague and possibly difficult to sue over as far as I can tell.
When my boss Burt calls a meeting with me, Ernie (one of my peers) is always invited.
That is generally weird. Ask your boss about it. Tell him point blank that if the agenda includes performance related issues of yourself or your team, you would like it to be a private conversation and you fail to see why Ernie needs to be there. He at least owes you an ...
No-one has suggested that I have been demoted from the position of
being Adam’s and David’s supervisor. Why is he acting as if he is
In a toxic workplace you can be demoted with zero notice. If he's acting like you're demoted maybe you have been but that won't keep them from blaming you for 100% of what goes wrong even the stuff ...
I am curious at what point a negative performance review is essentially a dismissal.
At the point where someone with authority to do so says "this is not good enough, you are dismissed, pack up your stuff and leave". Otherwise, it's just that, a review.
Whether you should treat it as a signal to quit on your own is opinion-based. For me there are ...
Well, you may definitely choose to leave after one poor review, but then you'd never get to work on the weak areas pointed to you in the "negative" review and overcome the shortcomings pointed out. If you really want to be make yourself better, take the review points, work on them and try to make it better.
After you have done your part, if you ...