If it was literally just that, I'd agree with you.
But it isn't. No one is "slain" for merely refusing a "reign over them".
Remember this is a "parable". That means it is very much like a poem, and uses metaphor.
Here's another explanation from scripture that is not a parable, and doesn't use metaphor, and will help you begin to get more of the accurate meaning --
"
6 God “will repay each person according to what they have done."
7 To those who by persistence in doing good seek glory, honor and immortality, he will give eternal life.
8 But for those who are self-seeking and who reject the truth and follow evil, there will be wrath and anger.
9 There will be trouble and distress for every human being who does evil: first for the Jew, then for the Gentile;
10 but glory, honor and peace for everyone who does good: first for the Jew, then for the Gentile.
11 For God does not show favoritism.
------
So, in reading in scripture, we learn by experience it is not possible to understand many things without reading entire books through, from beginning to end.
But after you do, then you learn much, and much becomes clear that was mistaken at first look, before one has the entire book in their mind.