Yes, I know that technique. I also know people who go for free books exclusively on Kindle. They don't want to pay for anything. That isn't helpful to people who are selling books in order to help support themselves and undermines the market for new book sales.
I know writers who tried giving their book away for free, and got almost no sales or good reviews afterwards. They aren't all selling terrible books either.
Would you seriously ask a taxi driver to give you free rides before they got paid? Or would you ask a teacher to work for six months unpaid in order to get a couple of years work later on?
I know this mentality is encouraged in some places with interns, but it is a luxury of people who can already support themselves.
I would not ask a taxi driver to give me free rides, but if I could invent and give away magical free teleportation, which would immediately obviate the need for taxi drivers, I would. If I could snap my fingers and conjure the revenants of past plumbers whose existence on the earthly plane served to do nothing but put plumbers out of business by providing services gratis, I'd do that too.
If I were a talented writer and had the ability to produce content as engaging as Peter Watts', I'd put it online for free.
Whatever 'harm' I might do to other authors or taxi drivers or plumbers with this practice is far outweighed by the good that is done to the world by its release.