The "If you're not happy submit a patch or shut up" is exactly the arrogant and absurd attitude that kills open source projects.
Similarly, cheald does not demand that users of open source projects contribute fixes for bugs. He also only stated that the exact opposite attitude is not a good idea.
Arguing either of those extremes is pointless: the discussion starts polarized and neither side will yield an inch. Introducing slavery into the discussion doesn't help.
Most authors of open source projects are interested in having their projects be used by many others. It is the usefulness to many others that provides a sense of accomplishment. If they don't pay some attention to problems those others encounter and for instance fix clear bugs in early releases, their chances of achieving that goal are lower. Observing this fact about the system is not argument in favor of slavery. There are no normative statements involved.
Similarly, if you, as a user of an open source project, want some bug fixed, the best way to go about it is often to write the code yourself and offer it for inclusion. That suggestion does not reduce them to slaves either.
To make a bazaar work, all parties involved have to be flexible in their expectations.
Maybe your experience with open-source is different. I think most contributors do it for joy, anyway.
Demanding unpaid labour has nothing to do with you or anyone else volunteering labour. My words cannot possibly be construed as saying volunteer work in open source is slavery.
"I do not believe that engineers creating software for other engineers results in exploitation."
Squeaky wheel driven development is not slavery. Users are "free" to demand features, and developers are "free" to ignore the requests. Your premise is absurd.