Valve seems like a nice enough place to work. But, I agree that much of GabeN's wealth would not have accumulated without (a) Labor exploitation in the Game Development Industry in general and (b) Consumer exploitation through DRM and the DMCA.

GabeN (and, e.g., TSwift) might not have directly, intentionally engaged in exploitation, but they have benefited from systems that institutionalize exploitation. (Sometimes, when the mask slips, people supporting those systems will claim the systems can't be profitable without the exploitation, in an attempt to justify the exploitation as a necessary "sacrifice" to Profit.)