As the Cowen vs. Rationalism spat shows, the harshest critics of rationalism are rationalists. Cowen, Noah, and Wilkinson, all of whom are smart, empirically minded, and Platonists, meet the criteria of being rationalists, and the Rationality community holds them in high regard. That’s part of what makes rationalism unique from other ‘cliques’. You wouldn’t expect the harshest Sanders critics to be Sanders supporters; same for Trump and Trump supporters (although as the alt-right Trump backlash shows, sometimes they are).
Also paradoxically, the most ardent defenders of philosophy are not liberal arts people–but rather mathematicians, physicists (except Neil Degresse Tyson), and programmers. You would think that math-minded people wouldn’t care that much about philosophy, but it’s the opposite, as explained in the posts Math, Physics, and Philosophy: Linked Together, Philosophy as a STEM Subject, and The Post-2008 ‘Philosophy Boom’.
For example, in 2007 Y Combinator founder Paul Graham put out a piece critical of philosophy, How to Do Philosophy. Soon after, J Somers, a programmer, wrote a biting retort. Physicists want to be philosophers, philosophers want to be physicists, economists want to be physicists, and physicists want to be economists.
Philosophy, much like abstract math, is about antecedents. For example, the antecedent of Bernie Sanders is John Rawls, who was inspired by Locke, Rousseau, and Mills.