Comment on "Black holes constrain varying constants"

A recent paper [DDL] claims that the increase of the proton electric charge e leads to a (forbidden) decrease of black hole entropy, therefore, possible evidence for variation of $\alpha=e^2/\hbar c$ [alpha] must be interpreted as a decrease of the speed of light. We argue that purely theoretical consideration of black holes possibly cannot give any model-independent limitations on variation of fundamental constants.