It's difficult to explain succinctly. SAFe is the embodiment of the kind of enterprise bureaucracy that agile was rejecting. Take a look at the principles espoused by the Agile Manifesto:

* Individuals and interactions over processes and tools

* Working software over comprehensive documentation

* Customer collaboration over contract negotiation

* Responding to change over following a plan

Now imagine what the exact opposite of this would look like, and then take a look at SAFe.