The american pallet is simply different and all our breads tend to be sweeter. The other part of this is that amercian breads tend to only use 1 grain, wheat. And they tend to either use whole wheat or bleached wheat.

Even when something is a "9 grain" bread, usually what that actually means is it's wheat bread with other grains in the crust.

Very hard to find a rye bread in the US.