It's human nature to be social, to share, to get reaffirmation, to be recognized... Zuckerberg and other social media CEO's tapped into these psychological needs and were smart enough to create platforms to satisfied these needs. Along with the benefits to connect, there are the consequences that bad elements will take advantage of.
The more citizens share on these platforms, the more Facebook stock and others go up, and the richer Zuckerberg and his bedfellows become by selling the personal info to advertisers.