As any honest scientist ought to be (cannot help but be) after all these years. Models don't lie ... modelers do. Models cannot lie as they do not know facts from falsehoods or right from wrong. Modelers should know these things but apparently do not.
I took time to read through this paper with a little more attention. Here a couple of paragraphs show that the climate 'scientists' would not have passed a normal engineering course:
"Strangely, GISS does not subtract their estimated urbanization bias from the current temperatures — their program adds degrees to the early unbiased temperatures, which is “rewriting history”.
NASA-GISS never verified their adjustments to prove they were actually removing urbanization biases from their data !
Once they had written their computer program, they merely assumed it would work."
These are not engineers
It is not like there are a lot of USHCN observation stations. Each should have its own raw and corrected/homogenized information with a formal manual signoff from the data keeper that the corrected/homogenized data has been verified (any change worked as intended) and validated (the change has been checked as correct). I get the feeling that there is a slapdash attitude in NASA-GISS to this data and if it shows more or less what they want it to then that is all that is required. Also by altering the past values - which were correct - instead of altering current values to remove UHI effects - they are again obfuscating what they are doing and making their corrections far more difficult to externally validate (which is probably the reason).
"The rules are simple: They lie to us. We know they are lying. They know we know they are lying, but they keep lying to us and we keep pretending to believe them."