If one needs the code to be maintained, not supporting may mean that the code may stop being maintained, which may mean that one will stop being able to use it in the future.
This may or may not be related to ethics, depending on what one calls or defines as ethics, but the reality is that free rides always carry a risk, even if there is no ethical obligation to pay for the ride. Of course, that depends on what value one gives to the code, and stuff like the cost of not being able to use it in the future due to lack of maintenance, or the cost of having to put in effort to maintain it oneself. But while there are no such ethical obligations tied to the use of some free software per se, imo there are ethics (or "ethics") tied to the interdepedencies and connections within such a social system in the sense of it being sustainable and able to self-perpetuate.
