Real Madrid defense isn't very bad, you are too much saying this. I can agree if you state they are not strong enough, but claiming they are very bad, totally not true.
It depends on what to compare, but in general I agree that Real's defense remained at the proper level even after the departure of Varan and Ramos. By the way, it is interesting that after the departure of Ronaldo, Benzema's talent and strength were revealed in full force.