There are perfectly valid reasons do disagree with physical private property, but repudiating copyright does not entail repudiating private property.
Physical goods have a significant difference, which makes property, if not indispensable, at least reasonably sensible: scarcity. Each tangible good is scarce, and its use by multiple people is conflictive. Property as an institution reduces conflict by determining who can use each good at any time. Copyrighted goods have no need for such mechanism - you can just create more.
See "Against Intellectual Property": http://mises.org/journals/jls/15_2/15_2_1.pdf
So, I cannot use your code. Many open source projects are developed by volunteers around the world, they will also not be able to legally use your code. If this is your intent, that is fine, it is your choice. Usually that is not what people intend when they try to put their code in the public domain.
For all I know the MIT license might be (say) invalid in France, because it's written in the wrong language, or invalid in Russia because the the first paragraph isn't written in ALL CAPS, or invalid in Taiwan because it doesn't expressly waive moral rights to the integrity of the work.
It seems to preempt the question you are asking. I get the sense that the "old-fashioned property" in the last sentence is referring to physical stuff as much as to software.
If he thinks so little of software copyright because it's "old-fashioned" and cancer-ridden, shouldn't he think the same of physical property law? Is this the kind of person that would steal your wallet too?