It's more like a bonded job, rather than "servitude". For the visa holder, they get to work in the US, theoretically at US local wages (or more), in return the sponsoring company gets an employee that is tied to that job.

If the US Dept Of Labor and/or the local state department are incorrectly measuring a) the local wage for the position and/or b) whether or not the company has made a good faith effort to find a local employee and failed (both conditions of an H1B position), then that is a failure of regulation, not of the concept of the visa itself.