Knowledge graphs for text (the focus of the article) seem narrowly-scoped since they require "objective" facts and relations to be practical. Capturing the subjective and transient perspective of observations made by multiple observers (which is what we actually have access to) is more complicated.

For example, asking the same person the same question may yield different answers based on their mood or other environmental or situational factors. Who's asking the question can also matter, as does the specific phrasing of the question.