That isn't necessarily true. Right now it is impossible to know just how prevalent the DO bias is on the ACGME side, because roughly half of 4th year DO students still apply through the AOA - including most of the tippy top students gunning for ROADS specialties. More realistically I think many ACGME programs simply do not receive many qualified DO applications currently - I work for a PD and this is exactly what he said. Come 2020 I suspect programs that were once thought to be DO unfriendly will 'miraculously' flip when the highest qualified DO applications start landing on the PDs desk.
And in the case of this one Rads applicant. It is easy to pick out one of the tiny handful of DO students applying to such a competetive specialty on the ACGME side and scream DO bias. You could pick one MD student with similar scores and find the same kind of interview/reject list. It doesn't mean anything until every DO is applying through the ACGME match.
Now I am not saying there is no DO bias, but SDN is making it out to be much worse than it is.