Bill --
You want to redirect the conversation to the question "why do copyright owners insist on describing copyright as a property right, rather than say as a regulatory privilege or a tort?" Fair enough. If I took a bit more time for research, I could probably come up with a very sophisticated answer, digging up 18th Century texts to support my position. But instead I'll give you a much simpler one, one that might not satisfy the philosophers, historians, and economists among your readers, but one that happens to be accurate (and will probably work for most lawyers): Because pretty much everyone refers to copyright as a form of property. Contrary to the premise of your post, it's not just "copyright owners" who use the term "property" in this context; it's exceedingly common for those on all points of the copyright spectrum.
There we have it: the more opponents collude by using the "eye-pea" term, the more the monopolists can point to this as "proof" that copyright and patents are property, not monopolies.
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