The DM is the only one with the full picture of the story, and shouldn't be questioned at every step, I agree with that notion.Under normal circumstance that might be true, but when addressing a DM there are different rules of etiquette in place. If you're running a game and one of your players points out that you're using the grapple rules wrong (to pick a random example), the DM has every right to be annoyed as he's supposed to be in control of the game and its rules, to the point of breaking them for reasons he shouldn't have to explain, and the player's comment becomes disruptive and irritating. It's backseat DMing, when the right thing to do is to stay silent and possibly take it up in private between sessions. If this kind of disruption happens regularly, it gets much worse.
When a complete stranger who is invited to observe a game publicly says the DM is using the grapple rules wrong, he's stepping out of line. This is not okay, and it's a rare DM who'll find it to be acceptable behavior.
However this isn't people actively interrupting the game (unless Ben was referring to Ian, Kyle and the guys questioning him), these are people commenting, for better or worse you can't stop people expressing their views on the Internet (YouTube or elsewhere) so your only weapon is, quite literally, to ignore them.
As I said, people should stop repeating whatever they think should be done every single episode, absolutely.
Whether they stop or not, you can do nothing but ignore them and consider it astrotufing, like people going "first!" In comments sections.