If you cannot comprehend the idea that work computers or phones can have software that is approved for one purpose, but not for others, then this discussion can

If you cannot comprehend the idea that work computers or phones can have software that is approved for one purpose, but not for others, then this discussion can't go anywhere. If you work at a healthcare organization, you may have Slack, but that doesn't necessarily mean you can message people's PHI. At a financial institution, you may have email, but that doesn't necessarily mean you can email PII. At CIA, you may have Signal, but that doesn't mean you can discuss ongoing military operations in it. I have already linked to policy that explicitly says non-public DoD information is not approved for Signal. I find it literally not believable that you don't understand this concept, so I'll have to chalk this one up to motivated reasoning damaging your ability to interpret English.