Here's the deal ... a video showing N3on -- a streamer/YouTuber popular with the Gen-Z crowd -- was posted to Kick showing the 19-year-old and his entourage stopped by deputies in West Hollywood. Check out the vid ... N3on opens the door and starts shouting questions at the cops about why they're handcuffing his associate -- before officers told them not to move and then commanded him and his friends to put their hands on the headrests in front of them.