I think it's well known that controversial comments get more "hits" than vanilla ones and if you have a look a the titles of a very high percentage of his videos they're all worded to get a reaction and more hits just so he can make money ... on that basis I think the guy's a complete ******* and woudn't believe a word he says.
My own personal experience having spent about 1 to 2 hrs a day for a month, listening to and comparing different streamers and DAC's they very definitely do make a difference.
Just my 2p's worth.