I somehow missed that. His proposal sounds much more narrow however, targeting only companies that have become a "sole provider of some functions". I do think breaking up the monopoly is a no-brainer in this scenario.
My issue here isn't with the idea that we do something about large tech companies. It's the proposal to abridge legal freedom of speech, masquerading as an attempt to protect free speech. OP is presenting this as an objective argument about freedom, when really they just don't like where the lines are drawn.