Credit monitoring always seemed to me like a scam ala antivirus, but in all fairness I have never purchased it either.
It is a scam - on multiple levels - first you get credit monitoring, but to the companies, it's a sales lead to try to sell you more of their protection / reports. It'd be a shame if something were to happen to your credit score.
Second, if a financial institution lent money to someone pretending to be me and this damages the rating these credit bureaus assign to me, why do I have to get involved? We have, as a society, let these companies get away with making us believe their lack of due diligence is our fault.
I don't know enough about the law to know why we can't sue these companies for libel.