I have never claimed that there is. I shall never argue that the is.
There are, though, principles that enable folks to function better in groups, that make for harmonious human relationships. One of them is to show some modicum of respect to another member of our human species. I know well that it is hard to show any respect to certain individuals. However, this is more for you than for the drunken bum, the slob, or Dick Cheney: if you have self-respect, if you have a noble character, it is you who will refrain from (moral) judgment …because you don’t want to be a ‘moralist.’
Yes, there is a real difference between the two concepts.
An “ethicist” does research in the field of ethics, or applies ethics in his/her profession. Or an ethicist develops ethical theories and systems.
In contrast, a “moralist” is someone who tells others how to live; and often is a prohibitionist of some kind or is a sexual-snoop who is obsessed with sex and functions as a puritanical ‘safe-guarder of the morals’ delving into what is acceptable to show to the public, etc. A moralist often attempts to scare people by dire warnings.