If you send an email from gmail to me, you don't get to ask that it be deleted just because you decide to delete your own gmail account. (Well you can ask but it would be unreasonable to comply. Same, if arguably less strongly, for comments you've made on posts or in threads on social media.)
1. if you want your data removed, companies HAVE to remove your data
2. if you don't want your data stored, companies CANNOT store your data
and then a bunch of if-when-then-else-must-cannot-time-dependent-legal-stuff