>There is a huge power differential between an employee and an employer

Usually yes, but not necessarily. Some highly skilled employees are absolutely vital, to the extent that them abruptly quitting would be more catastrophic for the employer than for them. Think database admin, C-levels, etc.

>Politics don't matter if you make brake pads or run a hobby shop.

I disagree. Even in a hobby shop, someone vocally espousing views that are abhorrent to their coworkers (like death to Jews for example) is going to be a drag on morale and productivity. If I have an employee who is spewing antisemitism and I have Jewish employees who don't want to listen to that garbage at work, should I not be able to fire them? My Jewish employees should just have to deal with it or quit?