Just jumping in here to note that if you think this piece, which is essentially, an Op-Ed piece written by Trump Jr. that does little but cite anecdotes, constitutes "proof," you have a very, very loose definition of the term.
Also, since the Right is so dead set against Gov intervention in the free market and so opposed to prudential regulation and inclined to give private companies a very long leash, that conservatives are so apoplectic about private info companies determining how to distribute info on their platforms, strikes me as, shall we say, a bit inconsistent. I say, if Payday Lenders and For-Profit Colleges are free to shaft consumers (as recent Trump Admin policies would suggest), Facebook is free to determine how to disseminate info on its platforms. (Interestingly, Facebook is also one of the prime disseminators of right wing conspiracy BS, so there's that.)
I would also note that, despite cries about media bias (there's no doubt that bias exists in most media outlets), the experience of Fox teaches us clearly that the Right is not concerned about media bias, per se, but left wing media bias specifically; right wing media bias is just fine. I strongly suspect that were left wing bias to disappear completely tomorrow, and the media were dominated by right leaning outlets, folks like Heathme would largely not utter a peep in complaint. There are now plenty of right wing media outlets now, so for God's sake, quit whining about it and quit acting as if the thought of media bias is so offensive. You clearly like it, just the right kind.