Why? Because Pluto TV wants you to watch within its ecosystem where they can display advertisements tailored to you and track viewing habits. An M3U link strips away the user interface, ads, and tracking—making it undesirable for their business model.
TiviMate, arguably the best IPTV player for Android TV, has a hidden feature. It can pull Pluto TV channels from its own internal database. pluto tv iptv m3u playlist link
The glowing blue text on the forum was the digital equivalent of a treasure map: https://pluto.tv . pluto tv iptv m3u playlist link
Warning: These playlists are community-maintained and may go offline without notice. Use at your own risk. pluto tv iptv m3u playlist link