he never removes it even if that person is doing no more shit posts or account selling and no second chance is given.
To the former remark, The Pharmacist should be replacing spam tags with neutral feedback. Regarding the latter, account selling is a shady act and deserves negative feedback. Just because you've stopped doesn't mean that you still weren't shady.
If I have committed crimes in the past and decided to stop after I was caught, does that absolve me of all of them? No, of course not. Why would you think that the same thing happens here?
Deterrents exist for a reasonthere's no point of adding the negative trust in the first place if you can just get away scot-free after saying "sorry sir".