Facebook has a negative effect on society according to whom? How does a tool that allows you to connect to other people have a "negative effect on society"?
People get lynched and killed every day in my country (India) because of hate-speech on Facebook, not to mention all the fake news being spread via WhatsApp.
If Facebook were to disappear tomorrow, it would be a net positive for the world.
It’s not opt-in when the cancer has contaminated a significant chunk of the web with like buttons and other stalking scripts and when the majority of the world is using it as its preferred communication platform, meaning opting out is inconvenient.
This in comparison is fighting against people who just want a bit of peace and less sewage being dumped in their Facebook timeline.