The plain fact is that CNN does not fact check Hillary to the same degree they do Trump. They don’t dig into Clinton’s money laundering foundation to any degree at all, nothing equal to their exploration of Trump’s “birtherism”.
They want to be biased and partisan but don’t want anyone to notice that they are biased and partisan. It can’t work. It can’t be hidden. People aren’t that clueless. If bias and partisanship is your tactic, you have to do it openly.