Why is the bond length of H₂O₂ greater that bond length of O₂F₂?

We know that fluorine is a strongly electronegative element. So, it has tendency to attract electron density towards itself. Thus, in O₂F₂ , fluorine attracts electron densities towards itself resulting in smaller O-O bond. 

In H₂O₂, oxygen is not as strong an electronegative element as fluorine is. So, even though it does attract electron density towards itself but not to the extent and intensity of fluorine. So, H-H bond is not as affected as O-O bond in O₂F₂.