Well it is just how it came across I guess. Still "stupid" should not have been used when informing someone of a possible error. I have seen setups where breeders have provided whole room temperature on a thermostat without belly or back heat. This i agree is not left to assumption as you are now stating but does have a thermostat to control the temps. You also strongly imply that they NEED belly heat. This is not the case. There are many breeders and pet owners that use RHPs and Back heat. So your insistence in the previous comment about belly heat being a requirement is false. I did not state anything on the OPs setup just on the comment you made.
As far as the OP's set up goes. Yes I agree that there should be a thermostat setup with some type of heating element just in case temperatures do drop to keep temps stable. It would also be good to monitor temps and humidity going forward with a hygrometer and thermometer. Just my opinion.