I think you're overcomplicating it, from the accounts given of his behavior in other articles it seems like it was just a massive egotrip for him. He enjoyed the attention and clout he got from seemingly 'predicting' what was going to happen.

Is it not two different people? The dumbshit who shared the info with his friends, and then someone else in the group leaked it to the public. At least that's the impression I got so far.

“A social-media account overseen by a former U.S. Navy noncommissioned officer—a prominent online voice supporting Russia’s war on Ukraine—played a key role in the spread of intelligence documents allegedly leaked by Airman First Class Jack Teixeira, reposting files from obscure online chat rooms,”

I'm not sure what point you're trying to make