No, as Orozco plainly indicates, late fees are legal to charge, based upon administrative costs to the landlord:
Quote Quoting Orozco v. Casimoro
Appellant argues that, notwithstanding such language, late fee provisions in a residential lease are never valid, since the landlord is only entitled to interest on the late-paid rent as damages, which is easily ascertainable as a matter of law. Appellant's legal premise, however, is simply wrong. A landlord is not limited to interest as damages as a consequence of the late payment of money. He is also entitled to "'administrative costs reasonably related to collecting and accounting for'" late payments.
The issue with the late fees you describe is that they are excessive.