Yes, seems that Greitens violated the ethos of the SEALs, which can be found here.
Excerpted section that speaks to not advertising (bragging, in Greitens case) or seeking recognition (“ooh, ooh, elect me! I was a SEAL!!!”):
My loyalty to Country and Team is beyond reproach. I humbly serve as a guardian to my fellow Americans always ready to defend those who are unable to defend themselves. I do not advertise the nature of my work, nor seek recognition for my actions. I voluntarily accept the inherent hazards of my profession, placing the welfare and security of others before my own.
Then Greitens never led a platoon, and served only two more years after training, which the SEALs in the article took issue with, as well.
“When you commit to be a SEAL you are committing to the taxpayers to serve four years,” one SEAL explained. “It takes approximately two years to get through training, and the vast majority serve at least four more after they finish training out of a sense of obligation to each other. In our culture, it’s not just about getting your Trident then getting out to talk about it, especially when you never served in a platoon. There is very little respect for a guy who serves the bare minimum of two years after getting his Trident and then gets out, especially if he then promotes himself through being a SEAL which is expressly forbidden by our ethos.”