You gave some good context I missed - The (even) more technical (read: pretentious) explanation is that it's a tertiary source. As a general rule of thumb secondary sources are preferred over primary sources, but both are acceptable in the right academic context.
I do understand the "latest version" argument, and it is a weakness, but it's also a double edged sword - it means Wikipedia can also be more up-to-date than (almost) any other source for the information. Thats why I say there's "nothing specifically wrong about Wikipedia either" it can be held in similar regard to other tertiary sources and encyclopaedias - with all the problems that come with those.
I do understand the "latest version" argument, and it is a weakness, but it's also a double edged sword - it means Wikipedia can also be more up-to-date than (almost) any other source for the information. Thats why I say there's "nothing specifically wrong about Wikipedia either" it can be held in similar regard to other tertiary sources and encyclopaedias - with all the problems that come with those.