In a rather unique situation. While the ux person is not the highest paid, This person uses articles and a dominant voice to justify their decisions. Not saying they haven't provided good ux solutions but they are selling ux as its the answer to everything and above all, as the saying "if all you have is a hammer, everything looks like a nail" ux being the hammer in this case. Most people wont argue or voice their doubts as they don't completely understand ux. This ux person doesn't understand data and believes data cannot tell what ux research can.
they are basically this http://whatusersdo.com/blog/why-hippos-are-the-enemy-of-ux/
So what do you do when something like this happens? How do you point out the difference between solid decisions and personal preferences.