I cannot understand why you cannot understand it.
The blame lies 100% on the shoulders of Mitt Romney who is such a rotten politician, who ran such a smelly campaign, that even a discredited, disliked, failure beat him.
And people think Obama's constantly blaming Bush is wrong. We all gotta have a scapegoat don't we?
If people who think that is why we lost the last election are in charge of the 2016 campaign ... be prepared to lose again.
Maybe, once your Mitt Romney Derangement Syndrome MRDS© subsides a bit, you can look at the facts and see what the real cause is.
Just because YOU hate him does not mean everyone does.