All that is important to them is that a gazillion years ago, some goy might have milked a cow, adulterated the milk, yadda yadda.
What’s important is that there was a gezeiras Chazal which does not become nullified unless a beis din which is greater than the one which made the gezeirah (which doesn’t exist today) nullifies it.
For those who hold that cholov stam is sufficient for their hashkafah
You seem to ignore the fact that it’s a halachah shailah (whether today’s milk fits the gezeirah).