If not, why? If so, please provide US Federal code, or case law confirming this is the case.
US federal law pertaining to Fraud and related activity in connection with computers suggests that it is unlawful to:
Whether publicly-served log files are covered is really going to depend upon the information contained in the logs (i.e. if there are requests which include sensitive data) and the definition of "protected computer".
It's generally bad practice to expose log data, however, even if the logs do not clearly contain sensitive information, I'd say it is equally bad practice to go around reading other peoples' logs (even if it's not a criminal offense, you could still run afoul of a civil court if you're somehow using someone else's "semi-private" logs to your advantage).
Comments seem to be primarily focused on the definitions of legal terms and that's far beyond the scope of the answer - the judicial system hasn't figured it out yet, either.