Maybe because the personna they show on TV is different than what they are in real life. However, I don't think it should be that way. If so, then that is an act that they are doing and it shouldn't be that way. If you want to act, then go into movies.
When I see a supposedly adult host acting like a two year old, I tend to think that is the way they are off camera and I can't accept that. Therefore, the hosts I don't like..........to me, they probably act that way off camera and it turns me off completely.
I don't care if I don't know them.........all I see is them on TV acting like idiots and I don't care to know them anymore than that, because again, they probably always act like that. If they aren't that way in real life, then why act that way on TV?