Literally all social media sites have this in their TOS, they dont own your content, they need this in their TOS so they can host it on their site/make thumbnails/reformat it to fit the site
FIRST LINE LITERALLY SAYS YOU RETAIN THE RIGHTS TO ANY CONTENT YOU SUBMIT
hey if you wanna get real existential and full of weird dread and possible self hate and or self love this christmas here is your recommended reading;
Homunculus by Yamamato Hideo
Oyasumi Punpun by Asano Inio
Planetes by Makoto Yukimura