AMSU data aren't even temperatures to begin with, but rather measurements of radiation emitted from oxygen molecules. It would be a bit impossible for the inference of temperatures to take place using MSUs without the use of "altered" data. Your not-so-veiled implication more correctly references "adjustments". The article that you cited explained quite clearly the need for the adjustments. Did you not read your own reference? Here is a bit discussing the need for adjustments to both, surface and MSU records:

https://arstechnica.com/science/2016/01/thorough-not-thoroughly-fabricated-the-truth-about-global-temperature-data/

And here is a more detailed look at surface record adjustments from climate scientist Zeke Hausfather:

https://judithcurry.com/2014/07/07/understanding-adjustments-to-temperature-data/