They probably promised him a job once he got out for taking the fall for mnets fraud

I mean, this isn't really surprising. The fact of the matter is, while Ahn Joon Young wasn't solely responsible for the 'Produce' scandals, he was essentially the fall guy in the end. That is not to say he was without guilt, because his actions directly harmed individuals who participated in the show as well as defrauded those who paid money for their favorites. However, he personally took the greatest hit publicly as he was essentially made to be the face of the scandal- this is an INCREDIBLY COMMON business practice when any major corporation breaks rules or laws. You see it world wide- the face of the company takes the fall, and even if they have jail time or a fine they always take their severance pay and either find work within the company or at a new one, often in the same or an incredibly similar role to what they had before. It's like an unspoken understanding in the industry of "That's just business", which is why these people will always still find work, because corporations often know it wasn't just them, but somebody had to be made a target to take the heat off the company. Mnet definitely took a publicity hit, but they're clearly still going strong. There was no way this man was going to be completely out of the industry, but it is a little surprising they weren't able to keep this a bit quieter for the sake of the scandal. But he was always going to find similar work once he was out of prison, that's the corporate game when you're that high of a player from the beginning.