I think the co-mingling of the idea of individual control being necessary and being property is the problem here.
Charles Schultz created Peanuts and all the characters in that universe ( Charlie Brown, Snoopy, Lucy, ect.) This is an intellectual property.
If I make a bastardized Peanuts of this I am stealing and degrading his intellectually work, especially if I claim to be the creator of Peanuts.
TLDR: Just because something is easy to steal does not make it yours and does not make it stop being a property.
