[Yeah, because proxy indicators showed a decline when direct instrument measurements showed an increase in temperature where the data overlapped, therefore proxies are an unreliable source of temperature data.
hahaha, I dont think I have ever agreed with you before! yes, they are unreliable.
interestingly, the tree ring proxies that were kept and used in most of the spagetti graph contributors, are now losing their hockey stick shape since additional data has been added.
personally I think tree rings are useful to give a general range and direction of temperatures as long as they are not cherry picked to give evidence for a pre-formed conclusion. or manipulated to give overwhelming weight to a few outliers. eg. Mann's work