I've never been any good with authority.
Madness is a prerequisite of being in showbusiness.
There's still a great deal of bias about homosexuality.
Hmm... Death by mini bar, how glamorous.
The opulence of Wilde is a bit too florid for Sherlock, who is a much darker character, ... fascinated by the human condition, but also overwhelmed by it.
A lot of straight actors are actively searching for gay roles because it is something different to do.