Answer:
people believed they were cannibals
Step-by-step explanation:
that's kinda the obvious choice as the odd one out, but if you need more supporting evidence than that:
the romans persecuted literally everyone who looked at them wrong, if you don't worship their gods or emperor, the odds of you not getting killed is -10000
and of course, the other cultures and religions didn't like how fast and effective the christian missonaries were
hope this helps:)