Saying 'you will live like a king' is not the smartest thing. He should have said:
'Please consider that your local living costs are much lower than in Switzerland. We incorporate those differences in our offered rate like every other company does. Thanks for your understanding.'
So the tone was—yes—unprofessional, the attitude not. And even if this attitude is debatable, you have to allow the other party to express reasons for a lower offer in a negotiation.
'Please consider that your local living costs are much lower than in Switzerland. We incorporate those differences in our offered rate like every other company does. Thanks for your understanding.'
So the tone was—yes—unprofessional, the attitude not. And even if this attitude is debatable, you have to allow the other party to express reasons for a lower offer in a negotiation.