Because though he is really a heavily controversial person, his name still has some weight in it for being the founder of the famous but crappy McAfee Antivirus. Especially in 2017, having his name on a certain project's team page gives the illusion that that certain project is legitimate/relevant. Fortunately, for all the stupid things he's said(especially the tweet in question), he's slowly but surely losing relevancy and reputation even in the cryptocurrency markets.
EDIT: So it seems like on the 2 projects he heavily shilled(Skycoin and Apollo) and whereas he's supposed to be a team member, apparently his name is no longer on the team pages. Freakin LOL. Shilling failed.