The entire US business culture, which extends deeply into US culture as a whole, puts employers over employees at almost every turn. What protections workers in the US do have, businesses try to circumvent all the time, not to mention many things, such as the ADA have no concrete definitions for things like what a reasonable accommodation must be (they do have examples of generally accepted things, but it isn't a decree) which allows for all kinds of ways of non compliance.

Not to mention, its unfortunately common that exercising any rights workers have will often work against you, being passed up for promotions etc.

Its strange how much power we give employers over employees, and how regular people defend this, even when its actively working against them.