At this point, just two substantive issues have been raised (neither by Broslough): there seems to have been a mistake in the C14 date analysis, and some of the photographs appear to contain repetitive features.
The former issue is plausibly a simple mistake, and I wonder if it would have any bearing on the question of whether there is evidence of an airburst here. The latter seems more serious, if it indicates that pictures have been doctored, but, as the person raising the issue says, this may be cleared up by examining the originals.
While a religious agenda may well distort scholarship, it certainly does not have to. As the only (so far) comment on the Retraction Watch article says, "most of the challenges here are ad hominem against the authors – the same criticism we make about pseudo-science defenders."
[1] https://pubpeer.com/publications/37B87CAC48DE4BC98AD40E00330...