Bittorrent was the first p2p technology that gave copyright holders the ability to put their content on their own website (in the form of publishing a .torrent file), instead of doing it on third party sites/applications, thus sending their "customers" away from their web property.
Due to that many software vendors (including some major Linux distros) adopted bittorrent as a distribution mechanism, giving it enough credibility.
All other p2p technologies failed to show enough non-infringing activity on their networks, which gave authorities legal grounds to shut them down.