To answer that question, I’m going to first bring up the definition of ethical.
The word comes from the Greek root of ethos, meaning moral character. It means that someone is in the right moral sense, so truthful, honest, fair, etc. Noble and kind are part of that list. If someone was not noble or kind, it doesn’t make as much sense for them to still be an ethical person. I mean, Imagine if you knew someone who was unkind, and dishonorable. You wouldn’t still call them ethical, would you?
One thing that I think of when I think of ethical is smart and reasonable. If someone is noble and kind, that will help them become a more reasonable person, while on the other hand, if someone is dishonorable and unkind, that could get in the way of being reasonable, and might influence them to make bad decisions.