doesnt surprise me that this is intentional, most extras are for kobo bought books
I only have a lot of side loaded because before I got my kobo I used Kindle app on my iPod, so had a large collection of books, most of these I converted to ePub in December ready for my Vox (any new kindle books I use kindle app)
going forward it wont be much of an issue, as I get most of my new books from kobo
minor annoyance, but nothing that will stop me enjoying my kobo