Earlier quoted context omitted.
Then consider yourself surprised. Deleted data is actually deleted. Keeping it around is a huge liability.
I don't know how things work these days, but a few years ago, Google's GFS didn't support deletion. The "delete" flag only meant "don't replicate this data" and it was just simpler for them to keep it around until the disk died. Source: This was published by Google in their research papers on GFS. Sorry, can't remember which paper.
It also likely would reindex it, meaning that you can't find it if you go looking for it unless you happen to know which disk it's in already and it hasn't been overwritten yet.