I mean there definitely are penalties, but they only exist if you actually go to court. DMCA essentially serves as game of chicken with no one actually wanting to go to court.
Penalties and counter-suits require intentional misrepresentation by the claimant, which is so painfully unprovable that the existence of penalties for malicious claims may as well not exist. I mean I suppose it can stop some rando guy from sending out claims for lols, but stuff like what Microsoft and a number of other corps do is extremely predictable and certainly malicious in nature.
DMCA seems like an ideal place to have the winner pay all parties' attorney's fees, plus damages. It's usually pretty objective and easy to see whether something infringes.
My cynical view is that the half-measure (punishments for impersonation rather than spurious claims) just prevents well-intentioned protestors from highlighting the insanity of the whole system.