maybe that's not the only reason john mcafee to stop promoting ico because it's risking his reputation
What reputation? His reputation as a scammer and con-artist?
More likely he's just made enough money for now - he was charging $105,000 per tweet. No doubt he'll be back with another shady as hell scheme in a few months when the money runs out again.
You are right, as this is only business and money. I think if mCafee get a higher offer and payment, then he will come back and want to promote ico again.