From this article (via Slashdot).

Simon insists that his group does not oppose open-source software, or discussion of the issue, but fights to defend the notion that a strong system of proprietary rights offers the best avenue for the development of groundbreaking software by giving its inventors economic incentive to do so.

We're not against open source software, but we think the only acceptable incentive for innovation is the economic incentive. Open Source is thriving without economic incentives, and we're scared because our fundamental way of thinking is being challenged. So we're going to try and ignore the whole "open source" thing and hope it goes away if we don't talk about it.