Don’t bother engaging with them. They aren’t going to change their mind. That’s the downside with Lemmy. There are so few users that these obstinate trolls don’t get buried. Engaging with them just makes their bad takes and bad faith bs take up more space in a thread.
It’s possible they are a real person who’s been banned from most other platforms for spreading their bile and have settled here because the low engagement means their troll bait gets picked up, or they are a non US citizen trying to astroturf US political shit.