So indeed, doing the right thing will be a seemingly losing proposition, but the right thing is still not to use those "products".
Objecting to Stallman's objections will lead to no good. Only informing and teaching people, and transmitting Stallman's message, can eventually lead to some good.
Saying that Stallman is wrong is therefore wrong and bad.
Why is it bad? Because it leads to no good? That's your view, and I disagree - understanding that this approach doesn't lead to results is actually a way to let people like him understand that results come from a different strategy. In this sense, saying that he's wrong DOES good to his cause.