That's a fairly serious accusation to level. Google's bad behavior here is not that their compression algorithm ruined users photos. Google's bad behavior is running a compression algorithm at all.
That's not the point. I doubt that the engineers who worked on the compression algorithms would store their own precious photos using the same techniques.
Also, when was the last time you heard a banker say that everyone makes mistakes all the time.
Hi, I work on the processing algorithms at Google like the one here (not sure about this particular issue) and I use Google photos for all my old photos. People at Google read Hacker News and fix things, they just don't comment on specifics for things like this.