JaghataiKhan, the permanence of curse and horrormark is emphasized in the FAQ to discourage threads about how to remove curses and horrormarks. It has been asked time and again of the developers that a method of removal be added, and it has been refused just as many times. Illwinter has made this game the way they want it to be, and on certain issues they are not going to compromise on it. I do not claim to know all of the reasoning behind it.
For the record, I'm not a member of Illwinter, I just manage the bug threads and bug reporting on the forum as well as the FAQ and the DB (which was made to encourage modding and mapmaking). So if Illwinter decides to change something, then they will and that's that, but in the meanwhile I'm reporting things based on direct statements from the devs. YThe most relevant thread I could find was
here.