Absolutist beliefs without critical thinking skills.
Ever notice how a liberal starts Climate Change debates with "There is no debating that Climate Change is real/exists."
Critical thinking argues that everything is up for debate at all times. If a hypothesis is true, it will withstand third party scrutiny and empirical skepticism.
Modern Liberal Arts institutions discourage intellectual confrontation. The professors and students are not used to having their ideas and beliefs challenged, so, they haven't developed the skills necessary to defend their ideas and beliefs.
That's how we live in age where many will use "there is no debating ..." as an opening argument.