I don't really think "traitor" fits though, he was more like a logic rejecting zealot.He did go from a Vulcan princess to a human schoolteacher so that can't have been easy for his family to accept. Sybok may have been a rebellious traitor to Vulcan beliefs but at least he was Vulcan.
He had no intention of hurting anybody or causing physical damage, he just wanted folks to essentially "see the light" and follow him to a place of emotional salvation.
(even though he couldn't see that it was a pipe dream)