The reason why people say "don't eat bass" is mainly because of a highly successful, decades-long catch-and-release culture that promotes them the bass fish as sport fish rather than food.
Many anglers also believe that other freshwater fish like walleye, trout and panfish offer superior flavor and texture over bass fish.
Not eating bass fish, usually comes down to a combination of cultural, biological and even environmental factors.
Bass fish are high on the aquatic food chain and are susceptible to bioaccumulation and they often retain higher levels of environmental pollutants, like PCBs and mercury than non predatory fish.
Freshwater bass, especially the larger freshwater bass are also known to have a strong, muddy or even overly earthy taste that depends on the water body the bass fish live in.
Bass fish can also be quite scaly and bony, which makes the bass fish harder to fillet cleanly compared to panfish.
And many fisherman that do enjoy eating fish also prefer to throw bass fish back in the water to allow them to grow larger and instead opt to keep faster reproducing panfish like sunfish, bluegill or crappie fish instead.
And bass fish are also highly aggressive fish as well as predatory fish that also put up a strong, acrobatic fight when they become hooked on a fishhook.
So, instead of being a food source, the bass fish are prized as a fun "catch" instead due to the fight they put up.
And over 100 years ago, freshwater bass were also nearly fished to the point of extinction.
And so to save the species of bass fish, anglers and conservationists popularized the "catch and release" mantra.
Today bass are instead treated with a high reverence in the angling community and keeping a large bass for the dinner table and to eat can even sometimes be frowned upon or seen as even controversial.
Bass are okay to eat and I eat bass fish myself, but some prefer to throw them back.
I find that bass fish to me tastes pretty good as does my mom.