Okay, I agree with that. People who rent apartments generally don't pay too close attention to property taxes because it has an indirect effect on them. I don't agree with your overly simplistic idea of supply and demand when it comes to rentals though.
The law of supply and demand in a perfect free market is an abstraction but there are always issues in the real world because there is no such thing as a perfect free market because barriers prevent more supply from being created or limit the ability of buyers to choose not to buy. That said, when discussing policy it useful to ask what can be done to remove factors that prevent the market from functioning like a perfect free market. With rental housing it is important to understand that regulatory barriers discourage people from making rental units available so if you want cheaper rents you need to think carefully about what barriers are really needed. Adding more regulatory barriers is only going to make the problems worse.