I have seen various people (see e.g. comments here) dismissing this article using the argument that GR frame-dragging is second order in $v/c$ and therefore insignificant because $v << c$ for galactic rotation. However, I read in Zee's "Einstein gravity in a nutshell" that the induced angular velocity (i.e. the component of angular velocity with no angular momentum) goes as $ω \sim (GM/Rc²)(v/R)$, which appears 1st order in $v/c$.
Given the effective value of $(GM/Rc²)$ for a rotating disk is likely to be much larger than that of a sphere of comparable radius and mass, can Ludwig's work can be dismissed without running full GR numerical simulations on the galaxies Ludwig considers?