He wasn't just a bad influence in the crypto industry, he has a zombified influence on his followers to the point that they easily would think he's always right whenever he made a call. No questions asked, "just do it" kind of stuff because McAfee says so.
His influence was ... mixed. He made a lot of noise and helped increasing the awareness for Bitcoin.
On the other hand he did indeed
a lot of bad to the altcoin scene, among many other (ICO) scammers. And indeed, unfortunately, many followed his words because they were expecting that he did some background check for the projects he advertised.