[ephelon]

The author asserts that YC's capitalist purpose it at odds with the hacker ethos of free information.

I would argue that YC is investing in products, not ideas. It has been stated many times that ideas are not valuable in themselves; their value is derived from the execution of an idea.

Furthermore, building a product around some open technology provides a monetary means to improve the technology. If you look through the list of contributors to many prominent open source components I am certain that you will find people who contributed because they were building a product that used the technology.