There's no easy solution here
Nuke the site from orbit. It's the only way to be sure.
There's a big difference between requiring something to get a job (peeing in a cup) and making something a requirement after someone already has a job (requiring flu shots after a longtime policy of it being optional).
It's really not a big difference. You just need to get rid of the idea that once you are hired, you are entitled to that job for good, until you either become unprofitable or start stealing staplers. It's the employers money, and they should be free to spend it how they please.
How long until we finally consider a real alternative?
While the initiator is to blame for the situation each individual holds their own responsibility for how they respond.
Certainly not. If someone starst a fire in a theater, and a panic leads to a stampede, the only person responsible for anything that results is the arsonist - period.
Think of it this way, if a gunman entered a crowded room and shot some people, would it be acceptable to take him out with a grenade?
If he has body armor and is heavily armed, certainly. The context determines what the valid response should be.
Who's being naive about the effect that gun laws have on the culture?