I mean he just tweets about bitcoin so often. He may be thinking that he is guiding his followers out of bitcoin but what he could be doing is making them more curious that they will eventually buy like his son did. Bad publicity is still publicity eh?
I don't think Peter schiff can influence the market hugely, let's just say only a small fraction of people see those tweets, the market is bigger than just one man, the only tweet that made bitcoin pump hugely this year was the tweet where PayPal stated that the have started accepting crypto deposits, those kinds of tweets have what it takes to cause massive wave in the market cause they are positive about crypto, unlike Peter's tweets that his just busy bashing bitcoin up and down, I guess his just salty seeing bitcoin hit its ATH and still doing well, unlike the gold he's promoting that keeps dumping.