Obviously the problem is that it's completely unbalanced. Do people making copyright claims have the same threat? "By disputing this counter-claim, you agree that you could have your right to file any copyright claims revoked."
If not, then yeah, it's absolutely unfair.
It would be entirely reasonable for Youtube to block them from submitting the current style of claims and require them to submit actual, proper DMCA claims which open the claimant to all kinds of counterclaims, require the claimant to assert under the penalty of perjury that they own that content, etc.
But yeah, maybe requiring claimants to actually go through the official process would be better (albeit more work for YouTube).
Filing a claim automatically and conveniently is not protected by law. They could just as well say, "We have an automated system with a convenient interface for good-faith actors. If you show yourself to be acting in bad faith, you can exercise your legal claim in writing by sending it to this address: X. The postal system to that office is pretty bad, loses stuff all the time, so you'd better send it FedEx."
Remember, they don't have to be true.
I can choose to combat the copyright claim (and during this process you check a box that says "you agree that you could have your account deleted if you don't win this claim" (something like that)), or I can give the $1/year revenue I got from that video to the scummy company that files these claims.
To me that's $1/year lost revenue (no big deal, right?) but that company now gets the revenue from this video—and millions of other videos... so they're making mint and gambling that most users won't even try to appeal.