Just because there was no law that said "do not be an asshole" doesn't mean that an asshole is any less of an asshole.
Doing it at Bezos-scale makes it a Bezos-scale asshole problem.
I would only blame the government if they forced him to do this. He had free choice.
When slavery was legal, were the individual plantation owners terrible? Yes. However, it was the lack of government protections that allowed them to continue operating. Trying to draw the distinction between bezos and other billionaires feels like trying to compare one slave owner to the next and hoping that somehow that condemnation would make them grow a conscience.
Slavery didn't end in the US because abolitionists condemned slave owners. It ended because it was made illegal through the force of law (and in the end, a civil war).
Companies abusing their employees and the tax code won't go away because you dislike them. Those practices will only stop if the law changes.
We shouldn't be beholden to our employers to have good working conditions and we shouldn't be mad at uber wealthy companies for using the taxcode to avoid paying taxes.
There are 100s of individuals and companies doing exactly what Bezos has done. We solve nothing by blaming companies for working withing the confines of law and being shitty.
Blame legislators that have allowed for such a system to exist. Vote in primaries and public for politicians that are looking at making things better for the individual.