It's not demonstrative - food from higher up the pyramid is actually denser in nutrients and taste vastly better in my mind (we're talking beef vs lentils, not plankton vs lion).
Plenty of counterexamples. I think scallops are probably the best tasting seafood if not one of the best tasting foods period and they're filter feeders. Shrimp is pretty good as well. Meanwhile, bear tastes pretty bad.
True, and I vaguely recall a case or few where people showed off their rich tastes (for swordfish steaks, etc.) until their nerves & muscles didn't particularly work together.
But, back during the formative millennia of human nature, that wasn't a problem.