Yes this is a very small proportion of books (only 158, less than 0.6% of the database), which is why I haven’t been really concerned.
It’s also not like you’ll accidentally buy one. If you’re going to buy a book, you look at the summaries and reviews… pretty clear by that time 
But yes, they just aren’t that popular on the site right now, so only people looking for them are finding them. I will eventually add a filter, but not too worried about it as yet.
