I don't object in the least to snarky comments, I don't object in the least to critical comments, but I do have a mild objection to unsigned snark or criticism. By which I don't mean everybody should have an LJ handle or blog ID, but posting such comments anonymously is a lot like sniping from cover.
Also, the commenter's logic is rather flawed. I really don't buy that spending a year being treated for cancer is functionally or socially equivalent to choosing to spend a year caring for a child. For one thing, there's that whole voluntary/involuntary thing.