I dont evaluate my in game actions based on real world history. Charming people is evil, but its not on par with numerous other actions. It typically happens once or twice a campaign and its not an issue. I did have a player once who used charm in every possible situation they could. Eventually, I had to explain to them the character was a bit of a scum bag and heading down a path where they would have a knife at their throat and no friends to help. Its situational and abuse usually has repercussions. Being an assassin is the same. You cant reason your way out of being evil. Eventually it will catch up with you. I wont stop you from playing such a character, but I'll never agree to such being a good character.