> Does this pass for science in these fields, psychology and medicine? They summarize various statistics from prior papers as if they are trends across space and time (hello sample bias, are there papers that contradict their claims they are omitting because it doesn't fit their thesis?) and then make broad conclusions based on anecdotal evidence and sweeping theories.

I feel that if you've never heard of a meta-study then you must not be very deep into science at all - like, even undergraduates know what a meta-study is.