Yes, Dall is very effective in ROPE. But my point is that in those days there was an underlying assumption that if you were gay, then it was 'logical' for you to play the villain. Laird Cregar is an example of a gay character actor who was typed in villainous roles, like Webb was in the mid-40s. Eventually Fox reformulated Webb's image, putting him in a series of situation comedies (after the success of SITTING PRETTY) and then he was typecast in variations of the Belvedere character.
At least they were allowed to take on roles in films and they still had more opportunities than most African-American actors.
I liked Sidney Poitier's portrayal of a doctor in the 1950 film No Way Out, but in any older film, the black actors were playing either servants, or sidekicks to white people (like Charlie Chan's sidekick in the 1930s and 1940s films), or something along those lines.
Interesting that women seemed to have better roles back then than they do in most modern films. Actresses like Barbara Stanwyck and Gene Tierney got parts that modern actresses can only dream about.