You seem to misunderstand the point of the book. PSL's analysis is that people in the US are so thoroughly propagandized against socialism that they have no idea that the mounting crises facing our class do have solutions, but that those solutions only exist outside of the neoliberal framework that totally dominated all political discourse. It never purports to be a theoretical work on how to achieve revolutionary change, because that is not its goal. Rather, its goal is to convince people that socialism is worth fighting for because it is actually equipped to address their needs. But the PSL's position is that a revolutionary reorganization of society is a necessary precondition to achieve this, and agrees that ML organizing principles are the means to achieve that.
The problem with social democrats is not that they, too, advocate for a society that offers more favorable conditions to the workers. The problem is that they reject the necessity of a worker's state and are content to build welfare off the ill-gotten gains of imperialist extraction. The PSL absolutely rejects this.
No work can address every aspect of every debate. That's a ridiculous standard, and if you attempt to meet it you will fall short every time. It's entirely disingenuous to dismiss PSL as revisionist or socdem based on one piece of literature just because it is not attempting to present a framework for achieving revolution.
The PSL recognizes that the workers movement was so thoroughly defeated and dismantled in the US that the masses lost any sense of connection to the actual history and lessons of worker struggle. The PSL sees its task as reinjecting revolutionary Marxism into mass struggle, but also that ultimately the masses will need to learn these lessons by experiencing essentially the same failures of previous movements which have been erased from mass consciousness. The PSL cannot directly teach these lessons or directly manufacture the conditions to activate revolutionary potential, but it has an opportunity to reach more and more people as they experience the failure of other methods.
https://liberationschool.org/theory-and-revolution-addressing-the-break-of-ideological-continuity/
Ultra-leftists are quick to complain that PSL's tactics are clearly not "producing revolution", as evidenced by the continuation of imperialist rule in the US. But despite all of their supposed superior analysis, they fail to put forward a specific agenda that can accomplish that task, let alone actually carry it out themselves. In other words, why should anybody listen to a bunch of belligerent assholes on Twitter (as you have literally suggested), if they haven't even done the bare minimum of organizing a more effective alternative? Is the PSL building an organization that is up to the task of carrying out a revolution? Who knows? But at least they are building an organization, and one which is explicitly ML.