When you subtract the spin, the evidence is that Russia Today News reported true things about the American election that the mainstream media did not want reported, that this is the same sort of thing as stealing true emails from the Democrats and giving them to Julian Assange to publish, therefore the same authority as ultimately has charge of Russia Today News stole the emails.
The spy agencies do not in fact know anything about the hacking that is not known to everyone. The emails themselves reveal that the Democrats were spearphished. The spy agencies are just forming an opinion on it from the point of view of someone who finds the existence of news media outside the power of the United States Government outrageous.
It is just an opinion based on the same evidence as is available to every well informed person, and most well informed people have formed a different opinion.
That Russia Today News reports truths that the mainstream media do not is reported as a horrifying outrage that pretty much constitutes an act of war. How dare anyone mention stuff that goes against the Cathedral spin?