>> he was openly against Chassidim who did.”
> Any proof for that statement?
a secondary, but contemporaneous, proof – when Lubavitcher Rebbe was already sick, this was the peak moshichism (as many abandoned it after he passed away, not to be like another religion). A local mature Chabad-affiliated Rav said publicly (in front of ~100 people) that he called the secretariat and asked if he can somehow be of use during these difficult times. They responded – please say publicly that this meshugas is not coming from us. And so he did.