First off, I want to say that you are completely entitled to your own opinion. But, your logic perplexes me a bit. You say that you wouldn't want to eat a bass under 3-4 pounds because it wouldn't provide enough meat to feed 3-4 people (or feed you for 3-4 meals). So, what you are really saying is that you only target the larger species of fish because you can get "more bang for your buck." I do realize that you have a miniscule impact on the local fisheries but what you are doing is selectively targeting "larger" fish species, whatever they may be. This is not an ecologically sound method of fishing either. Fish size should not be an indicator of whether to eat a fish or not, with size limits applicable of course. From a conservation standpoint, a better philosophy might be to catch and eat fish that happen to reproduce faster than other species.
Another point I want to make is that there is a huge difference between freshwater and saltwater bass. Unlike our native saltwater bass (i.e. calico, sand, spotted), the bass that are caught in local lakes and reservoirs are most often non-native, farm-raised, genetically altered fish. In my opinion, conservation of these freshwater fish is not as critical.