Yeah, that's completely false. I've used one for the past 18 years and it still saves me from tickets. Add in Waze and I've got a pretty good defense running for me. If you understood how radar and laser work, you would understand that radar, and laser to a much smaller extent, spread out as they travel. LE maybe targeting a vehicle ahead of you and now you have been alerted. Nothing is fool proof but detectors are still incredibly useful.
But yeah, you do you.