Youtube has it's own system outside of the DMCA to handle copyright claims in which the claimant has all the power. If the poster of a video wants to appeal a copyright claim, they appeal directly to the claimant who gets to decide. You can then appeal to YT directly (good luck with that) but in the meantime the claimant can issue a "strike" on your account. 3 strikes and you are out. So instead of fighting claims, posters are encouraged to just roll with the punches and be glad they get any money. Youtubers at this point will openly say "I'd show a clip but then I won't make money on this video" even when that clip would 100% be fair-use.
Youtube designed this system after pressure from the major Movie / Music publishers to either give them stronger tools than the DMCA provides or face a blackout from these major publishers. They wanted final control over their IP on Youtube and they got it, damn the law. If they had to file real DMCA claims, these claims on obviously fair-use materials would disappear.