A couple things:
You are responsible for making sure your data is backed up. If you only had it on Google drive, you fucked up. Their durability 99.99999 or whatever is fantastic, but you should always do your own due diligence and back up your files. Again, if your only copy of data is on one medium, even if it's Drive-- you've messed up.
I know thats semi- victim blaming(or straight up victim blaming) and that doesn't excuse Google for screwing up. But shit happens. If you had this somewhere else, this is just a minor annoyance. Restore and move on.
That said, Google has always sucked at customer service. That's probably because, with Google, you are often the product, so they don't really have a good culture of taking care of customer issues. They seemed to have bungled the comms on this.
But people being people, even if this is fixed there are always going to be people that swear it's not. Because they are either crazy, vengeful, or because they truly Believe a file should be there (even if they are simply misremembering/wrong). At some point a company has to move towards and nip the complaints in the bud because there is always a subset of people that will continue to bitch about it forever.