>He is from the secular demographic

This is an understatement. He was purged from the military and jailed by Islamists/Gülenists/Erdoğan using fabricated evidence and cultist judges, for "attempting a secularist coup".

I don't think it is "essentially" for propaganda. This would happen regardless, propaganda is just a side-benefit. Saying that he's "just a space tourist" would be like calling scientists that go to Antarctica for experiments "polar tourists". It is definitely overblown by the government media though.