Zeke's antics were a blight on the league. Suspension handed down. There is no such thing as "going against" law enforcement and/or investigators. Whether he broke the law or was indicted/charged is irrelevant. The NFL must maintain a certain image. Zeke's actions were contrary to the image desired.
Then, when the 6 game suspension was handed down, Z and Jerry made the unwise choice of fighting it, rather than going for a lesser suspension. Suspensions that are handed down are mostly lessened when the player comes in and proclaims "I shouldn't have done that, sorry", or something to that effect. Jerry handled this very badly.
Put this in the real world and you can easily see the logic. An employer does not need the employee to "break the law" to fire them. That is what you are saying, in reality. In essence, think of it this way. Zeke was doing the equivalent of coming in late every day and missing days of work. The employer docked his pay and told him to stop.