It's a textbook case of how the less learned a person is, the more convinced they are that they're right.
Literal
Shallow-learning [na-adjective-な] person [the-more-ほど] self [subject-が] correct [quotative-と] is-thinking typical-example is [confirmation-ね].
A commentary sentence with a touch of the Dunning-Kruger effect. The key pattern is ~ほど, attached to a noun or adjective to mean 'the more X,' frequently paired with a resultant state or tendency — 'the more X, the more Y.' 浅学 ('shallow learning') is literary and slightly disparaging. The quotative と links 自分が正しい ('I am right') to 思っている as the content of the thought. The noun-ending 典型です names the whole phenomenon as 'a typical example.'