The idea of "intellectual property" has been so ingrained in many people that they simply cannot or will not recognize any difference between copying/distributing an idea (or a digital work) and stealing physical property. Generally, their (faulty) logic is that putting time and effort into creating something necessarily gives you absolute ownership of that thing, even if it's just an idea or a string of bytes.
I don't think you're giving the modern population enough credit. I'd argue that most people understand that there are cases where you can take something, and the original owner still has it. What's ingrained, rather, is a respect for the inventors, creators, originators of the world. We look to them with awe and, rightly or not, feel some low-level need to recognize and uphold that they came first with their creation.
As someone who has tried to argue against the idea of "intellectual property", this is the response I usually receive. Unfortunately, creating something and enforcing property rights on the ideas to "reward" the author doesn't make the system any better.
There's that idea in software development that it doesn't matter who came up with the idea first, but who executed it better. I actually think this is how the world should work. Who cares if you came up with an idea if you never acted on it? Why should you have the right to hold up innovation in that field?
Just get rid of "intellectual property" (at least patents) and let the people decide with their wallets.
