I think it was lsiberian and his wife who went out to visit Mark a couple summers ago and said he was a most gracious host and that his homebuilt/designed system was absolutely amazing. Both of which, I have no doubt. He really does know his stuff when it comes to building and designing a system.
That being said, once he's formed an opinion on something, changing it is like trying to move a mountain. I've also noticed that about some of his tech posts. Many times I've seen his HDMI posts involve a lengthy explanation of HDMI handshake issues (which there are many of) which require all that "stuff" to fix (supposedly). Honestly, I fixed an HDMI handshake issue with something small and cheap like you suggested. I have no idea why it works, but it does
He is definitely getting better. I think Kew or somebody called him out on calling a new member an idiot and he edited his post and apologized. Still, he paints an awful black and white version of things in some of his replies. Too black and white, especially for some who have no idea what he's talking about.
I have yet to develop that opinion, but I've never built speakers. I just read some of his obviously wrong comments about the most mundane stuff and feel compelled to correct it before it steers someone in the wrong direction. For example, he told one guy that splitting an HDMI signal to two televisions would require professional equipment that cost more than the guy's house (unsurprisingly, he stated it with immense confidence and a rather wordy explanation). I offered the alternative of trying out a ~$20 HDMI splitter...which worked perfectly for the guy. He seems to be getting better (for as rarely as I read posts these days), but he certainly at least used to be stuck in thinking about how technology worked decades ago.