Obviously if you hold even he cant carry/eat chalav stam that is a sepperate discussion
No, it’s not a separate discussion; this is the point. If I hold that you need the actual presence of a Yid for cholov Yisroel, and mirsus isn’t sufficient, then I hold Elmhurst milk is cholov akum for everyone, not just for me.
I can still accept that you follow a legitimate shittah, and I can trust your kashrus for other types of food, and you can be an eid by my kiddushin (if you’re not otherwise passul) but lifnei over/m’sayeia would apply (putting aside, as you say, other technical details).