Meh. It's a 54 years old officer. Not some youngster who fucked up his life by diving in a shallow pool.
He may very well have endangered the lives of many people.
I usually don't like that argument as it is very conditional but in this case he wasn't denouncing something or trying to be a whistleblower. He straight up tried to make an enemy army more effective at killing Ukrainians (and Germans to some extent ) because he was afraid of their nuclear weapons.
He got off easy. We don't know what documents exactly he leaked but stuff about training/weapons can really change a war. You might pass it as things they already knew but what if they didn't ?