I think the reason why this "fundamental problem" is existing on one social network and white not on other lies on how these two apps are structured. On facebo

I think the reason why this "fundamental problem" is existing on one social network and white not on other lies on how these two apps are structured. On facebook, there are two modes of creating your presence - personal page and business page. You have choice to approve or reject new friend request or kick an existing friend if s\he is causing any trouble. I don't have official data about trolls on business pages but I am sure it exists there. Contrary to this, on twitter anyone can start following you and wage a war against you. You can unfollow your followers but how many you will do? To avoid any harassment on twitter either users can share their tweets only with their particular lists or have a moderation on who is following them.