Why were christians persecuted in the roman empire?

While the Romans had a wide degree of religious tollerance in the lands they conquered, the Christians were a fast growing movement that were causing civil unrest.

People were annoyed with the intollerance of the Christians telling them their Gods were not real and inferior to their Jesus. But this was an annoyance at best and just made them unpopular.

When Rome burnt, Nero chose the unpopular sect as scapegoats and that turn the ire of the empire against them for many years to come.