What you say there seems consistent with the "poison" thesis. My point is that too much of a good thing can become toxic. Postmodernity is an excess of modernity, a turning of rational inquiry inwards and against the treasured myths and delusions that seem to hold society together.

So modern progress leads to postmodern jadedness and cynicism. It leads also to the progressives' complacency and infantilism, to the neoliberal, consumerist centrism and to the wokeness that make American liberals so incompetent in their war against the conservative savages. See, for instance, the overturning of Roe v Wade.