It's not even just that Bookworm Girl. I had only one collection set to sync - Sony Documentation which had the user guide in it. I thought I was being smart in avoiding the nothing sync and made 1 collection to sync. It started the auto sync and saw hundreds of books on the reader but it was set to sync only the one collection so it bleeping deleted everything else on the silly thing.
OMG I was SO mad!!
I will not make that mistake again if there's a future update & I do hope that the next person who manually organizes their books learns from my grief & avoids making it themself.