Manning stole hundreds of thousands of secrets and exposed them to the very same Wikileaks that "Trump is a traitor!" people point to as a known front for Russian intelligence. Manning did it knowing that it would expose our secrets to clear and present enemies -- jihadists who were killing our soldiers and Marines every day. He did this while wearing the uniform, under oath, a soldier deployed at war who was intentionally betraying his brothers in arms.
He should have been shot. He was already treated mercifully by the system by avoiding being tried as the traitor he is.
I will take no talk of "treason" seriously from anyone who celebrates this commutation. They don't understand the concept well enough to discuss it.