From a capitalist perspective it's ideal if your workers are on the verge of poverty, living paycheck to paycheck. That's exactly where you want them.
People in that situation won't complain. Won't stand up for themselves or their rights. Will take poor treatment and deal with it. Will work in unethical or even illegal ways and keep quiet because they have no choice.
Even better if you can tie people's health insurance to their job, then you've really got them by the balls.
UBI would put an end to all that, so it's no wonder business owners would lobby against it.