Curate, connect, and discover
Hey, I get that you don't like that person's stance, but they don't deserve to die or to relive their own trauma because of it. Don't dehumanize your enemies.
If you're at the point where the most substantial thing you could say to somebody is a threat, just silently wish the best for them.
Wish that someday they'll stop being an enemy. Wish for character growth.
(Note: This is not asking you to "fix them." That's not your job, and helping people with the mindset of "fixing them" is not actually that helpful. If they ask for civil discussion-- and are genuine-- then it's your choice whether you permit it or not, but don't try to force your point without listening to them. Don't "fix them." It very likely is not going to work, and will very likely instead give them a bad/worse taste in their mouth about you and what you represent. Sometimes it is best to leave people be, in all honesty. You don't have to save the world, doing what you can is perfectly acceptable. Promoting good-will and stability in your own space is just as-- if not more-- important as stepping outside of said space.)