The Whitehouse did not suggest Putin was involved, they stated it as fact. Call a spade a spade. With no direct evidence to present they said he WAS involved. They didn't stop at "evidence suggests it is likely", they said he is/was involved, period.  They also said, with nearly equal certainty, that Trump knew, but they provided no direct evidence. 

Everything they criticized Trump of, they are now doing; from this story to refusing to acknowledge the winner of the election. The difference: media accounts of Trump generally included a statement, within the first 2 sentences of a story that Trump had no evidence. With this, it comes much later in the stories, if at all.

This is primarily what Trump meant when he said the election was rigged, and post election, the media remains largely "rigged" as a dishonest broker of information.