...because apparently in the academic and climate community, that is all that is required to make your arguments infallibly legitimate:
This level of success in proposing research, and obtaining funding to conduct it, clearly places Dr. Mann among the most respected scientists in his field. Such success would not have been possible had he not met or exceeded the highest standards of his profession for proposing research...
Had Dr. Mann's conduct of his research been outside the range of accepted practices, it would have been impossible for him to receive so many awards and recognitions, which typically involve intense scrutiny from scientists who may or may not agree with his scientific conclusions...
Clearly, Dr. Mann's reporting of his research has been successful and judged to be outstanding by his peers. This would have been impossible had his activities in reporting his work been outside of accepted practices in his field.(From the Penn State non-Investigative Report regarding the ClimateGate scandal,
http://live.psu.edu/pdf/Final_Investigation_Report.pdf)
So basically, there's no need to actually question anyone's practices, research or methodologies because the
success in proposing research, and obtaining funding alone is proof that they are legit. (That's hardly the charitable attitude that the warm-mongers have regarding any science to the contrary funded by anyone else)
Just a casual browse of "expert" opinions on global warming has temperatures increasing anywhere from 5C to near nothing.
But you say it yourself that
There are no known similar warming episodes in the past to compare to. Perhaps that's why they feel the need to make so much of it up.