Why does one have to focus on being humane/considerate/farsighted instead of being rational, rather than focus on both? We don't have to pick one measuring stic

Why does one have to focus on being humane/considerate/farsighted instead of being rational, rather than focus on both? We don't have to pick one measuring stick. I certainly hope you don't think that being irrational will help you to be more humane/considerate/farsighted, or that being humane/considerate/farsighted means that one can't be rational.