Shouldn't is a funny idea, as is properly functioning.

HR should never be considered "on your side." It's hardly considered cynical to presume a subsection of a company to care more for the company's than an aggrieved employee who would likely stir up trouble.

If this behaviour is as rampant as it seems to be, what incentivization reinforced it? More of a tangent thought, but if this keeps occurring what is causing the disparaging treatment?

No. Organizations that protect employees do exist, they're called unions.

Unfortunately, it seems that the organizational culture in NA (and in South Asia, from my friends and family that work there) is extremely union hostile.

It is, though that wasn't always the case in the US; at their peak a third of workers belonged to a union.

And it is unfortunate, because workers in strongly unionized industries enjoy higher wages even if they do not belong to the union. The decline of unions in the US has gone hand in hand with the rise in inequality. A lot of the jobs that US politicians talk about bringing back were union jobs, but even if it were possible to bring those jobs back, I don't think they're talking about bringing back the unions.