incentivize or encourage you to reduce load during times of grid stress (super hot, super cold).
They are tasked with having to instantly supply a product the moment it is demanded. A lot of times that'll come in the form of cheaper energy prices during off peak hours vs higher energy price prices during on peak. They are ALSO tasked with having a regulated amount of reserves incase things get too hairy. In other words, if there is an issue of meeting that supply and demand, it is NOT because you had your AC at a certain temp.
But yes, I agree with you in that ultimately, you need to do what will keep you and your family comfortable. The passive aggressive energy efficient home thing is pretty lame. Tell them to pony up and pay for better windows and insulation in your home if they are that concerned.