The article does not touch upon why exactly android + encrypted chats.

But it does make sense not to give your employer access to your personal affairs. If I'd ever work for Google, I'll switch my and my families devices and accounts to Apple's (and other); if I'd ever work for Apple I'd switch them to Google; if I'd ever work for Microsoft I don't need to do anything :) because they have nothing I use or need (maybe LinkedIn, but I use that as a top of the funnel lead generator only).

Policies mean nothing when there's an interest involved.