I went off TiK because of his style as much as anything. Some of his arguments make sense, although his trying to explain basic economics in one video was painful to watch (I'm an economics graduate for my sins). He does, to his credit, try to examine history through number crunching rather than talk in generalities, so although I haven't seen the video that you mentioned I suspect that he tried the same approach in that video.With regards to TiK on YouTube, I stopped watching his videos recently when he made remarks alluding to the exaggeration of the Holocaust in a recent video
As for Market Garden, he is very keen to blame Gavin and Browning, seeming to think that he has found the Holy Grail for the failure of MG. He even produced a video (withdrawn after a couple of hours following advice from many viewers, including myself) accusing Anthony Beevor of lying in his book about MG.
The reality is that MG required a lot of things to go right to work, and that is why it failed. Personally if I was to blame one person it would be US Major General Paul L Williams who dictated the air plan should only have one lift a day. Others may disagree with this, as is their right.