Mmm... your quote (IDK where it's from) mentions them having consent from device owners, but your FBI link cautions on how to avoid getting infected by malware.

If they have consent, they're not really botnets. Botnets involve infecting devices without the owners knowing.

With consent, it wouldn't be much different from e.g. open WiFis at restaurants and hotels, companies using a single ISP and single public IPv4 address for all their employees, and most VPN services.