Historically that's not true. It has been custom among many communities, in the past and present' to name their faith, sects, and cities after their leaders, ethnic or nationality. For example, Isra'elites took their name from prophet Yaqub (Jacob); Judaism from Judah (the pervert); Hinduism from their country Hind; Buddhism from its founder, Lord Buddha; Jainism from its founder, Jain, and similarly Christianity took its name from Lord Christ.

However, the early followers of prophet Eass (as) used to call themselves 'Nazarene' - after his birth-place - the town of Nazereth. They even had their own Gospel - written by Jesus' scribe - his half-brother Barnabas.

Wa Salaam.