If you buy an EV you hopefully do so knowing full well the vehicle's constraints. You've figured out those constraints aren't a deal breaker for your known use cases. When being offered as a rental most people have no idea what the constraints of the vehicle are nor can they make informed decisions about them. So having anxiety about any of those, including charging, makes complete sense. A rental car should be as flexible as possible, not have a care and feeding schedule like you're buying a Mogwai.