He's an underdog
Because he gets blamed for getting too much attention and ripped for his inferior statistics, Tebow's supporters often come to his aid and revel in the "us against the world" mentality. There's also the matter of Tebow's team, which wasn't supposed to be very good and barely made it into the playoffs after ending the season with three straight losses. The Patriots were 13.5-point favorites vs. Denver in the playoffs, and won easily. The Patriots beat the Broncos twice in a span of a month from December to January.