"One thing that helped me immensely in my career is understanding that my relationship with a company is a business relationship"

That is just a culture thing. Most prominently in the US. In many cultures there is no clear boundary between personal relationships and business relationships. And why would there be? I would like to live in a world where kindness, dependability, punctuality, warmness, openness and forgiveness are values upheld both by natural and legal persons. And I have worked with many companies that have! As you can read in the comments, for every bad example you can find companies lead by empathic people that treat their employees humanely.

Google always pretended to be that company. And maybe they were for a long time. Now they've shifted. They really didn't have to but they did. The excuse of "it's just a business relationship" really is just that: an excuse. The symptom of a culture with values so bankrupt that it accepts citizens being treated poorly and then blames the victims for expecting to be treated humanely.

And yes, it saves you a lot of personal pain if you expect the worst from your employer from the outset. But is the world really better off if we all expect to treat each other like criminals?