In a vacuum, I find it hard to argue that, all other things being equal, there is no ma’aleh to eating only CY from the fact that R’ Moshe was matir chalav stam (under government regulation of course), still says that a baal nefesh should be machmir.
Practically however, all things are not equal. Sometimes being machmir for CY will impose hardships on their family, will impact other areas of life (a lessening of simchas chaim can make it harder for a person to be a kove’a itim, or harder to control other middos like patience and ka’as, sometimes it will give a person an unhealthy amount of arrogance (holier than thou attitude). Maybe being machmir in this will make it harder to be machmir in other areas (like yoshon which is probably a more important area to be machmir in).
So yes, pashtus is, all things being equal, it is better to be machmir about CY. But all things are never equal and people have to speak to their own rov and make a personal cheshbon hanefesh to determine if this chumra is right for them.