It's also hard to find well-reasoned anti-mathematics literature or well-reasoned anti-genetics literature or well-reasoned anti-vaccination literature or well-reasoned anti-industry literature outside of the radical fringe. For the same reasons, probably - there just aren't much of persuasive arguments that weren't thoroughly disproved by both theory and practice.

Valve is an interesting experiment in self-organisation, but I don't see how it's in any way anti-capitalist, unless one thinks capitalism is identical to Goldman Sachs. It is not. Capitalism is about freedom to pursue every option and to succeed and fail independently. It is completely wrong to assume capitalism mandates some kind of specific company structure - on the contrary, the whole point of it is to organize the economy and the society in a way that you can try any organisation and structure (or no structure at all, if you prefer) and let the evolutionary processes to lead the ones that are more successful and adaptive to survive, while wasteful and ineffective perish (yes, I know in reality it's not ideal at all, other factors often intervene and screw up the picture, but that is the basic idea). If it turns out Valve model is superior and brings immense success, people start to follow it and there will be hundreds and thousands of companies built like that. If it turns out it's not as great as it looks, Valve followers will fail and nobody would do it anymore. In both cases, it is entirely what capitalism is about!