@susannah I probably have more criticism for DS9 than I do for any other Star Trek, but this sort of thing is why I love Dukat. Because Dukat is Hitler, right? Or, at least, he's Goebbles, or some similarly highly placed Nazi.
He is, hands down, evil. He never stops being evil, and the show never frames him as a character who deserves to be forgiven. Yet it does humanize him. Evil can have hurt feelings, evil can be loved, but evil is always evil.
It's a vital lesson to internalize.