If Socratic philosophy is the greatest threat to state power, Stoicism is the framework for mass compliance. It's a psychological strategy for emotional management that replaces the traditional goals of inquiry. This system encourages individuals to obey authority and limit their emotional range to reach a state of internal comfort. This objective discourages the act of questioning. In this regard, it functions as an anti-philosophy.
The modern interest in Stoicism in my opinion is a move toward a secular version of the Christian experience. Modern Stoicism retains the Christian emphasis on submission and endurance while ignoring the superstitious elements inherent in Stoic physics, such as providential fatalism.
If your objective is to maintain a state of functioning passivity, Stoicism is the effective solution (but I wouldn't recommend it).
I don't think of stoicism as passive, though - it is just about responding rationally rather than irrationally, and one important aspect is focus on what can actually be modified, controlled or accomplished, not on fantasy. That idea seems crucial to modernity, where the main manner of control is to dangle outrage after outrage in front of everyone to keep them focused on spectacle and NOT focused on what they can actually, materially, physically do to change the world.
In some sense I agree, there is a level of defeatism in at least part of the wisdom of the stoics and very little questioning of authority. You do have the "If it's not right don't do it, if it's not true don't say it", and you are suppose to act on things if they are within your control. There's just no encouragement that you're more capable than you think or that you should do anything beyond "The best revenge is to be unlike him who performed the injury." That doesn't really topple oppressive regimes.
It's a bit of a interesting take, you should act with virtue, but there is no encouragement to act against oppression and question authority. It seems very much like something to ignore and hope there's not a clash.