“As to why some argue excuses in the name of Rav Moshe that don�t follow his teshvos, I would say they don�t know his teshuvos that well. However, to claim that these arguments are Rav Moshe�s is simply not true, and definitely not possible, since Rav Moshe wrote otherwise”
Agreed. You either have to say the responsum in vol 5 has been tampered with or that the explanation was misquoted etc. There is no other way to go around it.