The thing is: he's not saying "this particular piece of research seems questionable" - he's saying "because this particular piece of research seems questionable, measures based on it and lots of other, better sources should be reconsidered".
It is in fact quite similar in style to holocaust deniers (you brought that up, not I): look through the other side's data carefully, find the weakest parts and make a big show of proving those false and conclude that therefore it must all be lies. (And yes, the holocaust deniers often go one step further and just make stuff up)
In real science, you try to disprove the other side's strongest arguments, not their weakest ones.
Actually, from what I remember, holocaust deniers tend to make up stuff out of whole cloth, both for their arguments and against (for easier demolishing, see). Maybe they look at actual evidence now, but I haven't paid attention in years.
In any case, I really have no idea whether the data in question was critical to the argument that climate is warming faster than it was earlier (since pretty much everyone accepts that significant global warming has been going on since at least the 1700s; the arguments are in the causes and details), but I just object to the hammering of the "deny", "denial", "denier" refrain.
It is in fact quite similar in style to holocaust deniers (you brought that up, not I): look through the other side's data carefully, find the weakest parts and make a big show of proving those false and conclude that therefore it must all be lies. (And yes, the holocaust deniers often go one step further and just make stuff up)
In real science, you try to disprove the other side's strongest arguments, not their weakest ones.