true but not quite. They strip it. Store the original and the meta data in their own database (because data on people is what gives them value) then they serve the stripped down quality one.
Are you sure it's not stripped out on the client before anything is sent to the server?
It would actually be really interesting to see a list of which apps strip metadata early on the client side vs. which retain it on their server and merely strip data from what is shared to other users...
It'd be hard or impossible to distinguish which ones strip it on the backend and discard the original image and EXIF data vs. ones who retain some of the EXIF data in some way. Just because they don't strip it on the client doesn't necessarily imply they're storing the metadata on the backend. (It just leaves the possibility open.)
Unless they're willfully doing something illegal, when you ask for your data under GDPR you should be able to see if they kept the original images or EXIF metadata, or if they discarded it.
Of course I'm totally ready to accept that most of those companies just lie and hide some of the data they gather on their users.
It would actually be really interesting to see a list of which apps strip metadata early on the client side vs. which retain it on their server and merely strip data from what is shared to other users...