The phrase "entire blame" means that someone is being held responsible for a situation or mistake all by themselves, without anyone else sharing the responsibility. Full definition
We have been trying to strangle the Cuban revolution for 15 years, forcing Cuba to become completely dependent on the Soviet Union and putting the entire blame on Castro for the consequences of that dependence — which may include the Cuban intervention in Africa. (religion-online.org)
When they all face criticism he comes out and takes the entire blame. (justarsenal.com)