塩対応 is used to describe idols' or singers' attitude towards their fans, which is cool or rather unfriendly. キャラ has some meanings, and in your sentence it means he/she is just pretending to have such a character to try to attract or please him/her fans. It implies that he/she has really a different character. ペン is slang meaning a fan/fans as you say. I didn't know it. 欲目 is overestimating someone out of affection or something like that. So, your sentence means: Some fans say his/her unfriendly is just a performance, not his/her own character. I don't agree with them. They just overestimate him/her because they love him/her too much.