That surprised me as well, I'm sure I've heard him say before that nonfree software is 100% unethical even on a free platform.
Perhaps he realises that having steam + valve games would be a huge net win for desktop linux use.
Even if you had mainly nonfree software , in theory desktop linux would still be quite a free system in the sense that there would be a level playing field amongst software devs.
Actually, that does seem to fit with the rational behind the LGPL. If you're going to write free software that replicates a proprietary program or library's functionality without adding anything new, rms believes you should make it available to the widest possible audience with the hope that more contributions will trickle back. However, I'm also sure I've heard him say that nonfree software is unequivocally unethical even on a free platform. Hell, didn't he say recently something about not being able to justify using proprietary medical equipment to save his life unless he immediately would embark on a quest to produce a free equivalent? Maybe he makes a distinction between trying to free future adopters from total proprietariness (i.e. in the case of games and LGPL'd libraries) versus trying to make people who have already taken the red pill 100% free.
Even the most zealous are rarely devoid of all nuance.
Note he actually says "Nonfree games (like other nonfree programs) are unethical". That one believes an act is unethical is different from believing it will have a net negative effect vs not performing the act, and there's often a lot of nuance to be had when something is ethically questionable.
Consider the periodically-raised question of taking control of a botnet in order to shut it down. Opinions on this range from "totally ethical" to "totally unethical", even as much of the "totally unethical" crowd would probably admit that shutting down the botnet is a net good vs not doing so.
Sometimes, "X is unethical" doesn't mean "no good will come of X", it means "we need a third option". RMS believes non-free software is unethical, almost surely believes the existence of software in general is a net good, and that Free Software is the "third option".
I don't think I've ever read an argument suggesting that shutting down a botnet (as long as that is all you do) would be unethical, more that it would technically be illegal.
I'm sure I've heard Stallman say in the past that software cannot possibly be in any way good unless it is free.
Perhaps he realises that having steam + valve games would be a huge net win for desktop linux use.
Even if you had mainly nonfree software , in theory desktop linux would still be quite a free system in the sense that there would be a level playing field amongst software devs.