I'm not a fan of Apple, but I think Cook's strategy here is very reasonable. iPhone is a walled garden since day one. People who really want freedom of speech have a huge reason not to use an iPhone since there are smartphones. It's not really a userbase he can attract anyways. This way in turn he keeps a huge market open for sales and as one of the biggest US companies in the Chinese market I bet he can also use that to trade favors with US politicians for insights into the market and soft influence over the Chinese government.