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.
Without reading the paper, I'm about 99% positive it also would mark the data as unused, which would allow the disk space to be reclaimed and overridden. Disks aren't write once.
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.
GFS is ancient obsolete technology that is no longer used (the whitepaper was published almost two decades ago, and it described a system already built and in use!). Also, I don't think you're interpreting it correctly either.
Under GDPR I'm fairly certain that they've implemented actual deletion. GDPR even requires companies to go so far as to scan old tapes to delete user records on request by a 30-day deadline, iirc.
