Comment on "Sequential Single-Pion Production Explaining the Dibaryon "$d^*(2380)$" Peak"

In arxiv: 2102.05575 a two-step process $pn \to (pp) \pi^- \to (\Delta N) \pi^- \to (d \pi^+) \pi^-$ was calculated by using experimental total cross sections for the single-pion production processes $pn \to pp \pi^-(I=0)$ and $pp \to d \pi^+$. As a result the authors obtain a resonance-like structure for the total $pn \to d\pi^+\pi^-$ cross section of about the right size and width of the observed $d^*(2380)$ peak at an energy about 40 MeV below the $d^*(2380)$ mass. We object both the results of the sequential process calculation and its presentation as an alternative to the dibaryon interpretation.