“There’s no issue hanaah by chalav stam.”
There’s no issur hanaah by mamash cholov akum either, but you still can’t feed it to a fellow Jew.
“The point is that eating chalav stam is not assur, but baal tashchis is.”
Lifnei iver is. Would you criticize him for not giving pork to his Reform friend?
“This guy put his chumrah over an actual halachah.”
Again, it’s not a chumrah no matter how many times you repeat it. Some people might keep it “l’chumrah,” this guy clearly keeps it l’halachah. People are not required to hold by Reb Moshe’s kulah. This is 100% about you wanting everyone to hold exactly like you, then you accuse us of being guilty of exactly what you’re doing.