I like Tim Vickery, but he's not God. It's his opinion and he's right and wrong about people like the rest of us. He might have more background knowledge and context for his opinions than us, but that's doesn't guarantee accuracy in the slightest.
I agree with the comment that said it feels like there's almost a slightly personal element to the comments re Martinez. Whether they've had discussions in the past or Vickery just doesn't rate Martinez, it does feel like there's slightly more to it.