It discusses how actresses were equated with prostitutes, and were frequently the mistresses of powerful men. The story of Dorothy Jordan and the Duke of Clarence reminds me of Irene Adler and the King of Bohemia, except for the illegitimate children. Also, as a contralto opera singer, Irene Adler would have been suited for trouser roles. Here called "breeches" roles:
The exhibit explores the "breeches" roles that were so popular in the 17th & 18th century. These roles allowed women the freedom to go on stage dressed like men, but it also caused a stink because they weren't covered up!
So that's more reason for men like Wilhelm to think Irene is basically a slut, purely based on her singing career, regardless of how promiscuous she might actually be. I've heard that Irene Adler was modeled on Lillie Langtry, and in the story, the King called her an "adventuress" trying to blackmail him.
Unfortunately, so many adaptations seem to equate "adventuress" to criminal or whore, as if our mores haven't advanced one bit. I hate it.