Honestly I don't know, I think it would depend on how long ago the crime was and if there's a credible reason to believe they won't do it again. I do think there's a meaningful difference between "they murdered someone" and "they're a murderer", and in general I do prefer to describe people's actions as opposed to using "they're a ___" labels.
Just in case this is a leading question: there are many courtesies we extend some but not all people convicted of a crime. Bail, parole, etc.
Why is such a person wandering around free if they were convicted? Do you think prison sentences are not harsh enough?
Honestly I don't know, I think it would depend on how long ago the crime was and if there's a credible reason to believe they won't do it again. I do think there's a meaningful difference between "they murdered someone" and "they're a murderer", and in general I do prefer to describe people's actions as opposed to using "they're a ___" labels.