If one white man shoots someone, it is usually for isolated and unique reasons.
He is having a domestic squabble. Or he is hopped up on drugs. Or he is robbing someone. He acts alone for unique reasons. I can't think of any 'group' violence anywhere in the world except muslims, specifically muslims. They are the only group that acts destructively and insultingly for religious reasons. That I know of. That I hear about on the news every frigging day for the last 30 frigging years.