Why should we not allow dye in our food products?

So much research shows we should not allow food dye in our products. The research goes so far as even being linked to cancer. What more do we need to remove these harmful substances from our food? This can also cause issues like ADHD in children. We know these are not good for us and they are completely unnecessary. Additionally, we also have real food sources that produce these exact colors such as beets and turmeric.