What is the target audience for shotacon? Is it for women who want to fuck little boys or for men who want to be little boys who get molested?
Both.
You see, the entire reason the word straight shota exists is because of BL.
The term IIRC came from some magazine reader asking what the reverse of a lolicon in the magazine "Fan Road".
But given the context it was coined in, shotacon started out for female readers but became something for both genders depending on the artist and nature of work. And oneshota is usually male oriented.
TLDR: Straight shota usually is male oriented, gay shota is female oriented.
Exceptions sometimes apply (E.G all of Rifuru's oneshota works that are for both genders, or like shit like Boku no Pico(it's obviously meant for a male audience) conversely