I don't disagree with your conclusion, but I would like to point out something that I feel is important - my own takeaway from my post-modernism studies: that post-modernism is not an ideology where facts are optional, rather an understanding and awareness of that our observations and our interpretations of our observations are subjective and dictated by our internal narratives and ideologies.
This is where our language breaks down, where we struggle to agree on the meanings of words such as "truth" or "fact".
While not in the least bit official, I find it helpful to think of "facts" as evidence-based data that can be tested using the scientific process, and of "truth" as experience-based data that can only be evaluated subjectively. To do this, we need to be aware that there is an objective, universal reality that we are a part of as well as a subjective, personal reality that serves as an internal map of the external reality, along with all its experiential distortions.
I strongly believe that if we could all consider the differences between these two sets of realities and their often distinct sets of data, it would go a long way to us making peace with our differences and being better able to collaborate over what unifies us.