If you take someones intellectual property, they still have it too. If you take someones tangible property they don't have it anymore.

If you take somebody else's opportunity to monitize their ideas, then they don't have it anymore

Property is physically defined, and is justified as an extension of actions (I have a right to think for myself, therefore act on my own thoughts, therefore shouldn't be interfered with. I am taking the action of "storing this object I made" (for example), so to steal it is to infringe on my action is to infringe on my right to think for myself is to infringe on my rights).

"Intellectual property" is a bad analogy to physical property, isn't justified by such a chain of reasoning, and in fact the IP enforcers are infringing on the rights of the second inventor (or in our mess of a legal system, the person who failed to file papers with the government first).