I think this is a distinct possibility:
-Vox's demographic target is virtually a total overlap with the demographics of hipster Christians.
-Vox's demographic target includes virtually zero Catholics.
Vox's readership share that are hipster Christians must therefore be significantly higher than the share of the general population, and its Catholic readership must be significantly lower.
I was reminded of this because my pastor quoted Vox tonight of course.
There are plenty of liberal "Catholics" who completely swamp hipster Protestants in pure numbers, so probably not.