Chirac's case happened more than 3 decades ago. Perhaps the judiciary had a different understanding on the gravity of those crimes back then. Perhaps what Le Pen did was more serious.

If Le Pen won, or if she would make to the second round is meaningless. The election would be tainted by having her running. That people are burthurt that their pet right wing populist became ineligible is of no substance. If anything it proves the courts are independent, and not acting to please a subset of the people.