The email says they have no supervisors.

It says they have no supervisor _working for the township_. They do have at least two supervisors that were just sworn in for 6 years according to the meeting agenda posted before. I guess that means they are fulfilling their duties uncompensated and thus no compensation needs to be determined.

Ah, you're right. I got confused because the township managers were incorrectly referred to as "supervisors" earlier in the Twitter thread.