Natively officially links to WK book clubs, so it’s not weird at all. Example:
The main WK book clubs tend to be divided by level rather than content (from Absolute Beginner to Advanced). I started my Japanese reading with the Absolute Beginners Book Club, so I highly recommend it for those who hesitate to take the plunge. Natively members tend to be accomplished readers already (not all at the same level of course, but you need to have read a book to grade it), so the book clubs here tend to generally follow the WK Advanced pace or even faster. In any case, anyone wanting to read with a WK book club doesn’t even need to make a WK account, everything is public. They only need an account if they want to post.
Now that I think about it, I was reading spicy stuff since I was in junior high at least. I remember reading an SF novel recommended by my French teacher that was really wild on that front. So maybe it’s fine?
I know a manga about curry that is fairly spicy too (although I guess it’s mostly just fan service)