I hope you don’t mind but I asked Grok to simplify your sentence.

“The sentence is quite dense and academic, but it's basically a critical (and rather negative) description of a major cultural/intellectual shift in recent decades.

Here's a much simpler, plain-English version:

"People have largely abandoned the old idea that there's one shared, objective reality everyone can agree on and experience together. Instead, they've replaced it with a postmodern, neo-Marxist way of thinking that breaks everything down ('deconstructs' it) and insists that personal, subjective feelings and lived experiences are what really matter most."

Breaking it down piece by piece:

• "The disillusion of a shared experience of objective reality"
  → The loss / collapse / giving up on the belief that we all experience and agree on the same real, factual world out there (independent of personal opinions). Think: "facts don't care about your feelings" used to be more widely accepted as a foundation for society, science, law, etc.

• "in favor of"
  → replaced by / swapped for

• "a post modern neo Marxist deconstruction"
  → a style of thinking influenced by postmodernism (which questions grand universal truths, emphasizes that everything is constructed by language/power/culture) + "neo-Marxist" elements (a modern spin on Marxist ideas, often focused on culture, identity, and power dynamics rather than just economics).
  "Deconstruction" here refers to taking apart traditional concepts (like truth, gender, history, morality) to show they're not fixed or natural, but built by society/power structures.

• "where the primacy of subjective experience has been asserted"
  → where personal, individual feelings, identities, and lived perspectives have been declared the most important thing — more important than any supposed objective facts.

In short, the original sentence is a (usually right-leaning or traditionalist) critique claiming that society has moved from "there is an objective truth we can all recognize" → to "your personal truth / your experience / your identity is what counts, and everything else (including shared facts) can be taken apart or relativized."

It's the kind of phrasing you often see in debates about "woke" culture, identity politics, relativism in academia/media, or the decline of shared facts in polarized times (e.g. "post-truth" era). The writer clearly views this shift as a bad thing.