You're missing the point. This app is written by outside, for-profit companies who don't care about data security. And the app is so full of security holes that it means work email and work chat may be skimmed by people outside the organization.
This isn't a case of "don't use your work phone for personal stuff."
This is a case of e.g. "foreign criminal organizations can potentially steal American Social Security databases."
Yeah, but normally the MDM is used to prevent security breaches. Not create them.