There's a very obvious reason, and I'm surprised no one has mentioned it yet.
The enforcement of intellectual property drastically increases the total revenue for any given art industry, whether it is movies, music, games, etc. However, to rationalize intellectual property, you must accept two major claims
1) It is fair for tax money to be used for copyright enforcement, even if the tax money is coming from someone who would never purchase your art pieces.
2) Copyright enforcement is only practical through a large degree of government surveillance and control over media distribution channels. The large government necessary to provide this is acceptable.
When you accept the above two principals, it becomes very easy to argue for the typical left-leaning laundry list of political demands. You've already established taxation, low personal privacy, jail time for some forms of speech (i.e. linking to pirated material), using public money to artificially grow an industry, etc. etc.