In response to harsh words spoken against learning Chassidus, the Rebbe advises presenting sources from the Arizal, the Baal Shem Tov, the Rebbe Rashab, and even the Vilna Gaon linking its study to the Geulah. If the rabbi disagrees, he must state it openly; otherwise, he should retract publicly. This will at least deter such statements in the future.
https://www.torahrecordings.com/rebbe/igroskodesh/016/001/5786