1. No it doesn't scare mobile phone networks.
2. Radio amateurs who are testing this are reporting all manner of issues.
3. The source code was forked and people got their noses out of joint.
4. I see no evidence that this will scale anywhere near the penetration of mobile phone networks.
5. It shares the LoRA frequency bands that are miniscule compared with the spectrum use of mobile phones.

Edit: Removed item 3, there is a split, though apparently not strictly a fork, in the "meshcore" community, not "meshtastic". While I'm aware of these projects, and have read numerous posts from fellow radio amateurs, I'm not following closely, mainly because I have plenty of other amateur radio projects to pursue.