I agree with your sentiment but I don't think sarcasm is going to get you anything but downvotes. The person you're responding might be underinformed and/or hasty generalizing, but probably deserves a more constructive reply.
Nutpicking deserves to be mocked. There are plenty of progressive economists, spokespeople, or empowered politicians; any of them are fair game for criticism.
Criticism, yes, I just think a more enlightening reply would do more for the conversation. The way I like to think of it is that you're refuting an argument for the benefit of otherreaders of the comment who may not be well informed / are persuadable, rather than to oppose the person you're replying to. Think of it as communicating a thoughtful missive to someone (who honestly doesn't know) that has asked you "what's wrong with that comment?"
