Just observing his onscreen personality at face value: He's very loud and bold, erratic, yelling ridiculous things at the audience in a Philly accent (no offense to Philly on that ... it just lends itself to a particular stereotype, like he may as well be at a bar talking about the Eagles). When his investments are bad, you can just say oh, the guy is a blowhard, not basing his opinions on keen intellectual insight; it's all entertainment purposes and so on.
But there's another cynical angle that enters, maybe it's paranoid to say but I think it's plausible: Does he have personal stake in his advice? Does he have some connections at these companies telling him to boost the stocks on air? That would enter into the realm of fraud. I guess when people confidently urge others to make ruinous financial decisions, that kind of concern always enters into it.