It's not necessarily a "move" - not if it comes from different people.

This is a problem in a public forum. You're not debating one-on-one. You're debating N-on-M. When you think you have a point nailed down - people with safety concerns understand the tech, say - then someone else comes in and argues against you from their viewpoint.

(If it's the same person, then yes, it's either a "move", or it's just that they're arguing just to argue, and not listening at all. If so, just move on - one cannot reason with a brick wall.)