They are insane.
Deluded, at the very least.
I was getting a few letters like that some time ago. It got so when they arrived in my mailbox I just ripped it up and dropped it in the recycling on my way into the house. I don't need to waste any of my time with that bullcrap. Had it had a decent return address I was going to write back and point out the errors of their philosophy, but I really didn't want to waste my time on that either.
Solidarnosc! (The slogan of the Yugoslavian trade union the broke the Soviet grip on the nation.)
They took to doing that in these parts, too (without having the balls to give their own address, just the address of the church or assembly hall or whatever the fuck they call it), I guess as a response to the pandemic. I tore up the letter and mailed it back. So now it's phone calls. Pity the fool who finds me home ....