The security of Hidden Field Equations - sentence I am reading this paper "The security of Hidden Field Equations (HFE)"

and at the end of the page 3 the author wrote:


  The random oracle paradigm would be to ignore that the function
  formulae exist.


I know what is the random oracle paradigm but sincerily I do not understand why the

"The random oracle paradigm would be to ignore that the function
 formulae exist."

Could you explain me please what that sentence means?
Random oracles are used in cryptographic proofs as a way to abstract away a complex function, making the analysis easier (ie "ignore the actual function, and model it as a random oracle instead").

In the paragraphs before the sentence you highlighted, they propose to measure the "complexity" of an equation / function by the degree of its multivariate polynomial representation over $GF(2)$.

In the context of the surrounding paragraphs, I would interpret that sentence to mean


  The random oracle paradigm abstracts away the complexity of the function, which renders our complexity metric useless.