“anyone davening to the rebbe is not Chabad”
Personally,I appreciate you saying that. I must tell you tho, that those who do do that would be very angry at you for saying they are not Chabad and they would call you all sorts of names. Even tho you are correct. You would be called anti Chabad and accused of having an anti Chabad agenda. Unfortunately, it seems that defending the Torah as your Rabbeim taught it to you is not an excuse if someone thinks you are insulting their derech, regardless of how halachically questionable that derech is!