I had a very different reaction to this, because I just released a Rust library called ironbeam [0] without knowing anything about this. It was intended to be a pun on Apache Beam and the fact that iron can rust... I guess I'll have to live with it for now because it's way too high-effort to rename it after a stable release.
I can read that as applying personal phones hooked up to employer services. I think it's pretty common to force employees to consent allowing their employers to manage their device to get access to work email on it. I'd always assume that just mean they could remote wipe it, but maybe it's even worse than that.
Reading the post makes it sound like this only happens on managed devices; whether that means "owned and provided by work", "within the confines of the work profile on a BYOD devices", or both, I'm not 100% sure.