They had no other choice but to petition the emperor. However, that would place them in danger of being penalized even before reaching the emperor and presenting their petition.
Many years ago, when the Roman empire included the Land of Israel, decrees against the Jews abounded. One such decree forbade the circumcision of Jewish boys. The punishment was severe for those who disobeyed.
Throughout our long history the Jewish people have zealously guarded the mitzvah of circumcision, even during periods of religious rebellion and apostasy. Only once was there any weakness in the fulfillment of this mitzvah.