I'm having a hard time seeing the controversy here.
Anyone correct me if I'm wrong, but as I understand this there are two things the OS does to 'phone home':
1 - a connectivity check which would include a browser user-agent string
2 - phone model and os version/channel - because it needs this info get the right files to do OTA updates
I guess one isn't opt in, but is kinda necessary for a connected device OS, and two is opt-in. It sounds like Ubports keeps a simple record of the above info.
The website should not be confused with the phoning home. That's a separate issue.