  In the paper [Angelini M C, Parisi G, and Ricci-Tersenghi F, Ensemble
renormalization group for disordered systems, Phys. Rev. B 87 134201 (2013)] we
introduced a real-space renormalization group called Ensemble Renormalization
Group (ERG) and we applied it to the Edwards-Anderson model, obtaining
estimates for the critical exponents in good agreement with those from Monte
Carlo simulations. Recently the paper [Castellana M, Real-space
renormalization-group methods for hierarchical spin glasses, J. Phys. A: Math.
Theor. 52 445002 (2019)] re-examined the ERG method from a different
perspective, concluding that the previous results were wrong, and claiming that
the ERG method predicts trivially wrong critical exponents. In this comment we
explain why the conclusions reached by Castellana are wrong, as they are based
on a misinterpretation of finite-size effects. We conclude that the ERG method
remains a good RG method to obtain critical exponents in strongly disordered
models (if properly used).
