He didn't merely criticize their lack of credentials esp. the lack of geologists, but criticized how they practiced stratigraphy for collecting samples for the supposed shocked quartz, as well as going into a details thread showing why their claims of quartz shock were unrealistic, and pointing out that the presented evidence of the supposedly shocked quartz did not actually appear to show that at all.
There's a whole lot of problems with that paper, the science isn't there, the people who wrote it largely had no relevant scientific training and made many blunders, the evidence presented is unreliable, the analysis is deeply flawed. A number of trained scientists have weighed in now with substantial critiques of virtually every part of the evidence presented:
https://twitter.com/ChrisStantis/status/1440404380386160646
https://twitter.com/petrabonegirl/status/1440833392006688768
https://twitter.com/FlintDibble/status/1440416847841546247
https://twitter.com/MTB_Archaeology/status/14404733356876308...
https://twitter.com/elleryfrahm/status/1440510054369677314
https://twitter.com/NErbSatullo/status/1440615036691501059
https://twitter.com/MichaelDPress/status/1440654636705140747