With a rare exception or two, I've been blissfully ignoring Roger Pielke Jr's recent stuff for the last year or so as he slid into irrelevance. As long as I didn't read his stuff, I could keep open the possibility that he was doing something useful.
Or not, regarding the Marcott paper. The Oglaf comic is great though, but highly inappropriate.
Others have handled it, (Eli shows up in the comments at the link), but I'll just add the parallel I see between this and how James Annan spotted the Pielkean confusion between detection and estimation of climate change effect on disasters, way back when in 2006.* Back then, people were trying to estimate what aspect of disasters were climate change-related, which Pielke denounced as failing to scientifically detect climate change in disasters. They weren't doing detection until more recently, as the science improved and disaster dice started rolling 13s.
RPJr: You say X (percent of disaster damages) proves Y (climate change)
Rest of humanity: No, I said assuming Y, here's our estimate of X.
RPJr.: You're wrong to say X proves Y!
(paraphrasing, not actual quotes)
It's the same issue or even less valid with RPJr and the post-1850 hockey stick/wheelchair component in Marcott. The paper is very clear in that they're not attempting to prove the current rise in temps via proxies. They even warn you not to consider their estimate robust, and they indicate the modern record they add is not theirs.
I agree that the press release could be clearer, but also agree with Stoat that it doesn't matter. It's like a paper examining Mars' orbit around the sun, where a press release might confuse a reader to think it also was about the fact that earth orbits the sun. There's no controversy about whether the earth orbits the sun. And the paper's clear.
So, just more of the same from RPJr.
*I think I spotted it too but could never find where I wrote it, thus reducing my own claim to a bitter, bitter footnote.