Philpott starts by pointing out and criticizing other things McWilliams has written. Later he suggests McWilliams' article is part of "a careerist strategy." He labels McWilliams' arguments a bunch of nasty names: a "tedious moral screed" (Erik Marcus has criticized the word "screed" at Vegan.com), he calls McWilliams "moralistic" (when somebody says "X is wrong," if X is something you do and would like to continue to do, then that person is labeled "moralistic"), and he says McWilliams "adds nothing new or interesting" to the discussion of the ethics of eating meat (1. most of the arguments against eating meat are old: that doesn't mean they shouldn't be restated to reach new audiences and reframed to convince old 2. by writing about something quite specific--free-range meat is still morally problematic--McWilliams isn't merely repeating old talking points here 3. just because the arguments are not new, does that mean they are wrong). He questions why McWilliams is bothering to turn his attention to the wrongs of eating free-range meat.
Philpott writes a response to try convince us McWilliams is bad, untrustworthy, annoying. He hasn't written a response to engage with the content of McWilliams' argument. And I suppose that's understandable, since it is extremely hard to argue against the claim that killing animals for the pleasure of eating them is unnecessary. Pilpott then doesn't have to argue against McWilliams' conclusion:
"by choosing death for an animal, humans choose the seduction of taste over an animal's right to its future. Until someone can convincingly prove that this denial does not constitute unnecessary harm, I'll continue to view free-range farming and factory farming as gradations on the scale of cruelty."