it fits into two categories
Reasons why he would do it- like he is a gambler and perhaps made a bet, didn’t want to break record, etc.
Reasons why they think he did it based on the show and his history.
Since I dont watch it I only skimmed and didnt really pay attention..but for example, category is one he knows, etc.
He had discovered that Jeopardy was a palatable way to make a living.