Come on, man. We're talking about classified information, not general OPSEC advice. I worked in a SCIF. Literally every piece of equipment, down to each ethernet cable, has a sticker with its authorized classification level. This system exists for a reason, like making it impossible to accidently leak information to an uncleared contact in your personal phone. What Hegseth did (and is doing?) is illegal. It doesn't even matter what app is used.