There is no justification for beating someone, even if you think you are 100 percent right.

Especially since this was done publicly at a farbrengen. Anyone who claims to be Chabad is seen as an example of what a chasid should be. Ask for forgiveness, fast for two half-days, and donate the money saved on meals to tzedaka. I pray that from the deep abyss, you rise to the high roof. https://www.torahrecordings.com/rebbe/igroskodesh/011/009/3582