I struggle to grasp how this kind of libertarian vision of the world can possibly be maintained by anyone who actually observes how the world works.
No, markets don't self-regulate. Companies won't stop working with Amazon across the board, and those that do will be replaced by companies willing to work for less, because they're full of people willing to work for less.
We know that's how this works. We know that people and organizations alike (since they're run by people) under this system don't have libertarian principles, let alone the will power to stand up for them.
Most people do not, in fact, feel the sense of righteous indignation needed to make such decisions, nor the ability to freely disassociate from sources of income, because they'll quite literally end up out in the street if they do, so they go along with anything, and rightly so, because survival comes first.
The only force that has the ability to stop powerful corporations from exploiting people in this way (hiring those willing to work under terrible conditions, for terrible pay, etc.) is the state, with its monopoly on violence, by quite literally threatening the executives of the corporations with death or prison time for not complying.
But the same libertarian-minded people who think the market self-regulates also stand against using state power to control the corporations by force.
So here we are. The Profit Motive destroying everything, and a fervent group of people fortunate enough to have the wealth to make independent decisions to disassociate with parties that provide their income lecturing those who don't have that luxury about how they too should make such decisions.