Throughout Chumash, the Ramba"n goes after the ibn Ezra. The Ramba"n says in his introduction to the Chumash that his attitude toward the ibn Ezra is "תוכחה גלויה ואהבה מסותרת". In the introduction to the Yam Shel Shlomo, the Maharsha"l excoriates the Ramba"m for respecting the ibn Ezra, saying about the ibn Ezra: "לא היה בעל תלמודו".
Is there an authoritative text that identifies why the ibn Ezra receives all this flak? Was he considered a relative עם הארץ who wrote his perush based on his poetry rather than a mesorah or Chaza"l?