Jent,
you completley missed the point,
if j-fem has another rabbi (modern orthodox or otherwise) who argues on R Moshe you have no way of knowing wich one is correct it is only your (or your rabbi’s) OPINION that he (R’ Moshe) is correct.
You cannot look down on or blame someone who disagrees with this opinion the same way you woldnt look down on someone who disagrees with your opinion on what is considerd good food ect.