The crypto markets are full with retail investors that are very susceptible to media and in this case, to opinions from high profile personalities. A lot of people blamed Charlie Lee from selling all his LTC because he didn't want to be accused to trying to influence the litecoin price in his favor, but I agree with his decision, because it's that easy to influence the price among retail investors.
So I'm not surprised about the so called McAffee Effect. Most people don't even know what bitcoin is, so they definitely have no clue about the majority of altcoins out there. So if a "high profile crypto celebrity" makes a comment about a coin, they will take it for granted in invest blindly. Others will probably follow because they know about this effect, so in either cases, the coin will pump.
Many people depends on speculation on high profile people they easily think that if they follow it, money will come to them. Well it happen sometime but its too risky for a newbie to do this. Mcaffee affects so much on every coin he said and I do hope that his intention is right and not just to make money.