Same reason high-fructose corn syrup is an ingredient in bread and everyfuckingthingelse, because it's cheap and has some use in the recipe

If you want good bread, go buy some artisanal stone-ground wheat with honey and oats stuff from your local artisanal bakery. I miss the days when I could walk past Clear Flour at 4am and pick up some of their just-baked cinnamon walnut rolls.