Because you can get sued for firing them. Sued for multiples of their annual salary.

Then that's the heart of the problem, and it should be fixed.

How do you create laws that both

a) Protect a vulnerable class of people from being fired (say over 40 people)

and not

b) Require 30 forms when firring someone in that class for perfectly valid reasons

Seems really really hard to hit both. You need to err on one side or another.. which way do you go?

Document repeated negative performance or toxic behavior and then act on it.

There are plenty of people in non-vulnerable classes who regularly do indefensible things because they know their companies won't act on it.

Untie a person's ability to survive from their employment status. If we had universal healthcare and basic income then the necessity of most of the employment laws would cease to exist.

Not so simple. Is their suit likely to be won? Are the unemployed able to pay expensive lawyer fees?

In my case, I do not have the authority to fire someone.