There are two types of reviewers: The valuable ones that actually read a paper and try to understand it, and the worthless ones that look at title, abstract and who wrote it (usually easy to find out even in anonymous review). The first type catches these things, the second does not and quite often lets bad papers in and keeps good papers out. The second type is much more common.
Or to put it short: Peer review is broken, as there is no quality control in most cases.
Reviewed that for you.