You're talking about 3 very different things here.
1) You're saying social media isn't opt in because they're tracking users off of their social media platform. This doesn't have anything to do with social media, but rather the pages you're going to have chosen to use a service provided by Facebook to track users. They could use another behavior targeting service, but chose Facebook's.
2) You're saying Instagram deletion didn't work. It sounds like you deactivated it instead of deleted it. I haven't heard this be an issue (it'd be widely reported if it were)
3) You're saying it's not opt-in because people refer to it in the news. In that case, nothing is opt-out because people have the right to refer to anything they want. Making this opt-out would mean censoring other people from saying things online or referring to things online, because of your views.