“If I’m being kind to you but you think I’m being horrible, am I being kind or not?”
I think that they would be being kind because they might either be really mean usually and this is kind for them or the person they are talking to could be very sensitive and usually hangout with people that are ‘perfect’. They could also be giving the person ‘constructive criticism’. This would mean that they would be helping them (therefore being nice/kind) but the person they are talking to might take it the wrong way (therefore think they are being mean/horrible).
On the other hand the person might treat all their friends like this but it is actually quite horrible, which would mean they are being horrible but no one has told them so they don’t know, but they are still being mean.