I think one problem is that, due to general mistrust and paranoia regarding the "mainstream media," people tend to conflate bias with intentional fabrication and propaganda.
there have been numerous examples of fabricated information or outright propaganda in mainstream media in the past. Most recently the fake news stories regarding ISIS from ABC.
You mention "numerous examples of fabricated information or outright propaganda" and "fake news stories regarding ISIS from ABC" (stories, plural) but only cite one data point - a story for which the wrong video was used, and which was later retracted. And for which, as far as I understand, malicious intent has yet to be proven.
I understand it's considered axiomatic here to assume malice where stupidity would suffice as regards the media, but as you're attempting to argue against fabrication and deception by the media, your yourself are attempting to deceive readers here by conflating your case.
Perhaps you could add weight to your argument by listing the other fake news stories regarding ISIS from ABC?
https://www.foxnews.com/opinion/dan-gainor-fake-news-abc-fal...