The popular conception of science is really outdated in this respect. Peer review still matters, but most meaningful peer review happens post-publication, not pre-publication. People should not take published papers as reliable statements of "what the science says".

Scientists are not going to expend a lot of effort on the thankless work of peer review, taking time away from their own careers, purely out of professional integrity and the goodness of their hearts. And their competency to do so is uneven at best anyway. What happens when the people who wrote this paper review other people's data?