And yet, the latest poll by Monomuth shows Biden ahead by 4, CNN by 5, the Economist/YouGov shows him ahead by 6, Quinnipiac by 8, CNN by 11. Only Economict/YouGov has a recent Trump vs Sanders poll, and it shows the same results, Sanders +6.
Previously, the last major polls that show a comparison between the two Democratic candidates against Trump are IBD/TIPP with Biden +6 and Sanders +1, Grinnel/Selzer with Biden +4 and Sanders -1, Harvard-Harris with Biden +10 and Sanders +6, NBC News/WSJ with Biden +9 and Sanders +4.
Summarizing these five polls shows Biden with an average lead over Trump of 7, and Sanders with a lead of 3. I would believe these polls over a youtube video.