Southern Brooklyn Assemblyman William Colton shared a post on his public Facebook page calling Black Lives Matter a “hate group” and equating it to the Klu Klux Klan — which, he said, started out as a group of “well intentioned people” before becoming the notoriously violent white supremacist institution that it is today. “I support my Black friends but not BLM. I support my white friends but not the KKK. I don’t support hate groups,” the Aug. 9 post reads. When asked about the post, Colton — who has represented Bensonhurst, Bath Beach, and Gravesend in the state’s lower chamber for 23 years — claimed that he shared the message simply to …