I agree with the point your making. He' used a poor choice of words by saying they cheat you. I didn't watch the video where he said that so I'm not sure what context he was saying it in. Your right It's up to the photographer or who ever is buying the camera/lenses to do the research and know the difference in the apperture on different camera systems and sensor sizes. I've seen a couple videos from the guy but I don't follow everything he does so I don't really get why so many people take shots at him. The times I've heard him he's given his opion and sometimes I've agreed and other times I havent. I've heard him say both good and bad things about both canon and nikon. Im just not going to take a shot at the guy for saying they cheat you, I got what he meant.
Apparently you understand the actual point of communication, where the larger part of the internet merely bickers over the words used.
Why bicker over words? Would you mind if someone unfairly accused you of cheating?
The actual video is titled: "How Sony, Olympus, Panasonic, Canon, Nikon & Fuji Cheat You". Cheating is acting dishonesty or unfairly, in order to gain an advantage. Cheating is deceiving or tricking someone.
In the video, he quotes user reviews on Amazon.com and makes fun of people who were "misled" into buying the Panasonic 12-35/2.8 lens. "They paid $1,000 and they didn't get what they thought they were getting," he says; "Shame on Panasonic for marketing the lens like this."