The Senate summary is comprised of evidence from authoritative institutions and their overlords, the scriptural foundation a largely fact-free assessment yet the media insists on passing it off as unassailable fact. We agree that there is disinformation alright, just not on the same side.
Authoritative institutions and their overlords? You mean the FBI and US intelligence agencies I assume? What do you consider a legitimate source then, is it only legitimate if it backs up your predetermined narrative?

There are far more consequential threats to democracy than cyber-interference
Yes, there are and those need to be looked into but that does not mean that cyber interference should be ignored or downplayed. It has the ability to get into tampering actual vote counts for electronic voting, the swaying of opinions by targeted propaganda is dangerous enough in a culture were people don't check the 'facts' they get from facebook or twitter.

The sort of backchannel diplomacy that routinely happens between one administration and the next. Not a sign of collusion.
For a normal administration it would't be. This administration however has all sorts of alleged ties to illicit Russia money, sanctioned individuals, and the President himself has an obvious and undeniable man-crush on Putin (or he's beholden to him). He's only conducted actions such as sanctions against Russia when presented with veto-proof votes by Congress on the bill and even then he protests and says it has “clearly unconstitutional provisions” giving doubt in his intent to carry out the letter of the law.
Seeing as the line has changed from "there is no collusion" to "collusion isn't a crime" it seems they are coming to terms with what seems to actually be collusion which will probably end up being potential charges of criminal conspiracy between Russia and US individuals (how high up no one knows for sure yet).