“The only difference between living “inland from the coast” in this regard is that one area has seafood and the other doesn’t.”
If they are talking historically, then it makes sense. Until relatively recent times, agriculture was not very viable unless you were in an rich delta or flood plain, which tend to be found near the coasts. You could grow stuff in other areas if there was enough rainfall, but without knowledge of fertilizer, crop rotation, etc, that would only last a few years before the soil wouldn’t cooperate any more.
Well, there are plenty of inland river deltas and plains and agriculture is just as predominant inland as on the coast. We've had knowledge of fertilizer and crop rotation since the Old Testament. How recent the Old Testament times are in the scheme of events we are talking about here is, I guess, a matter of debate.