The problem with red anti-corrosion paint is that it makes it harder to spot actual corrosion when it happens. As one instance I'm tangentially aware of, I learned that US laws require bridges (unless otherwise grandfathered under historic paint colors) to be regularly repainted in bright colors closer to whites/yellows/blues/greens so that any red or dark corrosion patterns or even just badly aged/weathered paint become easier to spot from a distance.