I usually don’t mind ignoring people who are set on their silly ideas, but when I know they’re spreading FUD and discouraging others from digging deeper on Bitcoin it rubs me the wrong way.
Discussion
Don't try to convince them, if anything, try to convince the audience that might read along. That's usually less triggering.
Lately, I have been trying to engage in conversation with FUDsters for the sake of counteracting their effect and sharing useful information for anyone reading. It does help to focus on that.
But given everything I’ve been seeing and experiencing in Bitcoin circular economies around the world lately, it irks me a little when people who have never left their neighborhood spread FUD about something they know nothing about other than what they’ve read on the NYT 🙃
I can understand that. People in first world countries that criticize a network that's literally saving people in third world countries. People are able to transport their wealth and get out and you want to stop that and call it useless? Monstrous.
It’s an interesting problem. In the past I heard bitcoiners referencing Albert Jay Nock’s essay, Isaiah’s Job, to build up this idea of the project aiming for a remnant. The project idea has to “fester” and “corrupt” for awhile. 
https://mises.org/library/isaiahs-job