As very few people today (in the USA, anyway) are actually “Ovdei Kochavim U’Mazalos,” the term Cholov Akum as applied to milk taht is not supervised by a Yid, might be considered inaccurate. Cholov Stam is therefore an appropriate name to refer to milk not obtained from the cow under the supervision of a Jew.
The laws of milk have nothing to do with whether the non-Jew is an actual “Oved Kochavim U’Mazalos,”. The term is unimportant (in halacha); there are historical reasons for its usage (see rabbiofberlin and truth be told’s posts. But as I mentioned in my previous post, it is important in halacha to distinguish between milk which is unquestionably non-kosher and milk which is subject to machlokes. Therefore, the term “cholov stam” is not interchangeable with the term “cholov akum (as these terms are commonly used).