I suspect it's because the guilty parties see things in absolute terms. The categorization of creators, public, and opportunists demonstrate this well. There is going to be plenty of variation within these three groups. (My apologies to Ralph Sir Edward. I agree with your point, albeit as a generalization and not an absolute.)

In my case, I both agree and disagree with copyright. There are a multitude of reasons for this. In it's favour, copyright gives creators an opportunity to earn a living from their work. It also allows pecuniar compensation based upon how well the work is received. Yet I also see the value of the public domain.

I'll give you an example: the city that I live in has a chunk of land designated as "the commons." The land has had many uses over the centuries, but large chunks of it are of benefit to the public: parks, schools, hospitals, and cemeteries currently occupy this land. Or simply think of where you live: how much would you lose if you lost all of your public spaces? (Don't forget that roads are also public spaces.)

Now I know that the public domain is different. The public domain involves taking something that is owned and making it into something that is not owned. Unfortunately, it's something that we need to do if we want a literary public domain since writing doesn't exist until it is authored.