'Bad' is a pretty fundamental word in our language not easily removed. 'Barbaric' is different. We also don't sling around 'gay', 'retard', and 'ching chong'.
a) those qualities are something a person is born with b) they do not cause grievous harm to others
Meanwhile certain actions (such as practice of FGM) are both done by choice and cause harm to innocent victims. Which is why it is our right to call them barbaric.
Is there any human activity that you would not call barbaric - cannibalism? Slavery?
Anyhow, I don't truly care one way or another. I'm just saying I see where Amnesty is coming from. Generally I don't modify my language until there's a group specifically offended. That might not even be the case here and I might not mind offending FGM practitioners. But Amnesty is not trying to dehumanize people, because doing so in general leads to worse treatment of people.
That's 100% wrong (and is well addressed in the OP). Barbaric refers to the act itself. If Hungarians or Swedes decide to chop their girls' labia off, I will call that barbaric. And if it offends someone - I don't give a flying fuck. Just like we do not care if slave-owners are offended because we consider their practice barbaric.