Facebook isn’t stalking you. Those Facebook accesses are initiated by the SD home page.
These days, social media stuff is everywhere. The SD home page, like many pages on the internet, will display buttons for various social media sites like Facebook and Twitter. This is for the convenience of Facebook and Twitter users, so that they can share the SD home page with their friends with one simple click, and this helps to potentially spread the SD to new users, so it’s a good thing for the Dope.
If you click on the Facebook Like button and you’re not logged in, Facebook will ask you to log in. If you aren’t logged in because you’ve never had an account there, then the Like button obviously isn’t going to do anything useful unless you do create an account there.
There’s nothing scary about it. Most web sites these days recognize the importance of social media, and intentionally place social media buttons on their pages.