I'm actually not sure the usual social reasons apply here. He's already flattered their intelligence and I can't understand why someone would be offended by a public admission of disagreement. Also, assuming the posters he is referring to have high status here already (a reasonable assumption given that they are smart and post a lot) I can't see why they would be uncomfortable mentioned by name-- shoot the way this post presents them I'd be very pleased with myself if Phil was talking about me.

If there is some possible concern I'm missing Phil could at least send the people in question PMs, asking their permission to use them as examples.