I will open by saying that looking back, I was probably a little too dismissive of Greenwald. Truth be told, since Trump got elected, I've had less and less respect for Greenwald since the election--it feels like he's less interested in investigation topics like Russiagate and instead just tried to prove it wrong, however I was willing to dismiss that as just him not trusting intelligence services, until he bought the same scandal but about Hunter Biden without further question. Mind you, I have not seen Greenwald post the article he wrote that The Intercept tried to censor, and if such a posting exists I'd read it in an instant. However, I feel like Greenwald is less interested in doing actual journalism these days are more interested in just refusing to believe whatever narrative is being told to him--when it puts Trump in a bad light. Compare him to someone like Caitlin Johnstone, who refuses to believe both the good and the bad about Trump without much evidence. Has Greenwald ever mentioned Trump being quite a hawk on Russia? Or the near coup held in Venezuela? Or the constant escalation with China? To my knowledge, he has not.
To tackle a few of your claims head on, what do you mean when you say "have these emails been denied as false"? Joe Biden has denied them at least once--I believe twice, but I can't remember when the second time took place--that I'm aware of.
I will admit that, as one of the strongest critics of the Hunter Biden scandal, I have questioned the sources many times. However, I have only done such a thing when the source has either proven itself to be unreliable or when it doesn't make sense for it to be the source. For example, I doubted Wayne Allyn Root's claim due to him being a small figure in conservative journalism and as such, any damning information about Hunter Biden is not likely to come from him. With that said, I still personally tried to engage with the content and found the evidence to be lacking.
To end with, I will say that I would love to investigate Greenwald's claims of censorship at The Intercept even further, but he has not given me the evidence to do so. As it stands, it's he said she said, and I personally am siding with The Intercept until Greenwald provides me more reasons not to.