Because if it wasn't NASA would have had no reason to erase the high temp records of the 1930's and they wouldn't have needed to start pushing the "global warming" narrative during a climate low point roughly forty years ago.

There was absolutely NO reason to alter the historical climate records unless the current narrative is a fraud and they needed to make it look legit by altering historical records to "prove" the narrative.

Keep in mind, thermometers have been calibrated the same way for hundreds of years. The boiling point of water hasn't changed. Thermometers have been used to meticulously measure and record temperatures for a very long time. Yet somehow now NASA has felt the need to "homogenize" the historical climate records magically creating "global warming." And, they were dumb enough to get caught doing it.

It's a joke.

As with everything else, follow the money to see who is benefiting from the false narrative.