“Labeling something as avodah zarah is pretty serious, something that needs a posek or a talmid chacham”
No one (I hope so) is Labeling people here as Ovdei A”Z, rather its these acts that have concepts of AZ – these very methods have a ריח של ע”ז, and goes against some foundations of Yidishkeit. As for the very people committing them, they have been denounced by their very fellow Anti-Mashiachist’s as well. We are not the first ones here…However, I believe most of them are brainwashed from birth and no need to go to extreme saying:
“there are groups whose shchita I do not eat and whose wine I do not drink.”
On the contrary, Rav Shach ZT”L did label them as Kefirah. Almost every posek disagreed with him incl. Rav SZ Auerbach ZTL.