Unless you build your own, you have to trust your ISP to move packets, but you don’t have to rely on any third party services or give them your personal info to use social media.
Fully decentralized, open-source, and encrypted social networks exist. The only servers needed are your computer and the computers of the friends you communicate with. (See: Retroshare )
They’re just never going to get big because small, personal friend-to-friend networks can’t compete with the network effects of centralized media and a never-ending torrent of dopamine on tap.