@ Joseph
“If one is a member of a community or congregation that holds that Cholov Stam is Cholov Akum mamish, then eating CS is absolutely no different than eating CA, and carries the same negative spiritual consequences”
Sorry. Halacha does not exist in a bubble. Even if a particular Posek is machmir for himself and his congregation. Even if he thinks HaRav Moshe’s Psak is an error. The issue remains categorically a dispute among the Poskim (about a din d’rebonon by the way). He can disagree but he cannot pretend Rav Moshe’s psak doesn’t exist.
Now if he brings proofs against Rav Moshe’s Psak AND those proofs are deemed adequate by a majority of contemparary Poskim, AND it becomes the prevalent custom, then there might be something to talk about.
Until such time that Rav Moshe’s Psak becomes nidche (don’t hold your breath) nobody has the right to say that someone who is eating chalav Stam dairy products is eating trief mamash.