Because humans are a social species. Abstinence is unrealistic for most people https://shkspr.mobi/blog/2020/02/abstinence-isnt-safe-why-qu...
That said, I'm doing a social media fast for Lent. It's entirely possible that when Easter comes I might not go back to either Twitter or Facebook.
Most of my socializing has been and continues to be done in person, over text, or over email. I do miss out on updates from distant family and friends, but the interaction on Facebook was always shallow anyway, so I don't feel like I'm missing much.