"Some people are convinced that the "mainstream media" is a vast coordinated conspiracy and that most journalists have a liberal bias."

Thanks to Wikileaks, that's now established fact, and part of the historical record.  

"They will argue with you all day about it"

Because it's true.  Nobody with a brain thinks Wikileaks is "fake news."  You can't identify a single "fake" thing about it.  Not even one.  And yet "mainstream" publications like the Washington Post say Wikileaks is publishing "fake news."  Who should we trust?  A publication who has lied countless times in the past, or one who has never lied yet?  Wikileaks has never once, ever, published "fake news" and I challenge you to demontrate otherwise.

If you want evidence of WaPo's fake news, simply look at their Iraq War coverage.