1) I referred to no editors by their first names in that post, though I did in others. #623 was about an exchange between a director and an editor.
2) It was just lazy. Marty and Theresa are a lot easier to type, late at night when you've had a couple, than Scorcese and Schoomaker. Using first names might not be strictly according to Hoyle, and it's not something I'd do in formal writing, but it was clear.
2a) Thelma, not Theresa. Oops.
3) You say this on a forum where referring to politicians by their first name or nickname, e.g. W, Hillary, Osama, Al, Rudy, Bubba is the norm.