And even with current laws, where there "need not be a just cause", there are protections against unjust causes (e.g. because they found out you're jewish, or you're fat, or whatever) and "because a mob campaigned against one" can be added to that. "But, under current law the business could just say they fired them for their own neutral reasons?" Sure. Let them defend that in a lawsuit, if it happened to coincide with a mob campaign.