1. You have a controlling share in the company and don't give af (b/c you might lose customers and employees)
2. Everyone else (at the company) already completely or mostly agrees with your rants
3. You are so damn good at what you do that people have to put up with you
Let's be honest, the most common reason people do get away with personal political rants at companies is because they get lucky and are in Scenario 2.
This is another reason why everything is becoming more polarized. Companies are beginning to "lean" much more one direction or another. There is no reason to think that this will change anytime soon.