Hadith does not mention that the prostitute didn't consider her actions to be sin. I too am a very big sinner, may Allah forgive me, but I don't make halal that which Allah has declared haram. There's a big difference between a sinner and a misguided aalim who has corrupt aqaid and who misguide other people.
However I've never said that Ghamidi Sahab cannot be forgiven. I can never say that. I've no idea if I will die in a better state than Ghamidi or not. May Allah protect our Imaan.