It is not vadei treif, but the hechsher is considered unreliable (thus a safek treif) by most people who wouldn’t eat it, not just because they want to hold themselves to a higher madreiga or they are machmirim. ALL those I know who would eat cholov stam wouldn’t touch hn. It falls into the same category as triangle K.
I can’t speak for you wolf or people you know. But this is the case for everyone I know who won’t eat it. Which is basically everyone I know who considers themselves to be shomrei Kashrus.
No one suggested telling people who eat hn that they are eating treif