Most discussions about research findings are like that and HN is probably no exception. :-) "The sample size is too small" or "they didn't control for [x] effe

Most discussions about research findings are like that and HN is probably no exception. :-) "The sample size is too small" or "they didn't control for [x] effect" are the sort of gut armchair comments people make offhand, knowing it probably applies to any study if you get challenged. I assume that's the sentiment you reacted to and I agree it can be frustrating.