"Looks like the error bars need error bars…"

Hide the decline – the core:

Indeed, they did not simply “hide the decline”, their “hide the decline” was worse than we thought. Mann et al did not merely delete data after 1960, they deleted data from 1940 on, You can see the last point of the Briffa reconstruction (located at ~1940) peeking from behind the spaghetti in the graphic below:

Had Mann et al used the actual values, the decline would have been as shown in the accompanying graphic:

Looks like the error bars need error bars…