MavenspringrollsAlso there's something really funny about trying to rebut the idea that sniper has no counters (outside of another sniper) by providing a counterexample that requires two players.
The point of that section is that the counter to sniper is teamwork and positioning. He can only look at one place at a time and so anyone from literally anywhere else can kill him easily. The same example would've worked with scout, soldier, demo, even heavy doesn't matter. The problem with all of those however, is that they can't steal his identity and his tax return... Making it far less profitable to do so.
Edit: I should add that the theme of teamwork is kept up throughout the video and is mentioned explicitly more than once. Every class in the game is weak to a 2v1.
While I appreciate that you recognize that 2v1ing any class is how you beat them, and I think most newer or low div players still need to learn that, I think not having experience playing against the best snipers in the game doesn't fully inform your view. Spring rolls is correct that the mentality of "just hide and let your spy stab him" is really fucking stupid because all it takes is 1 engineer that hits half their shots to stop the spy.
Teams at the highest level of competition (at least in HL) have great difficulty stopping a good sniper from taking over the game, or they simply can't because the other sniper is having a really good game and killing 4-5 players before anyone can close the distance even if they do everything right on paper. There's no other class that can do this, because there is no other class that benefits from being very far away from the enemy. If you had jay on soldier, and he doesnt miss a single rocket, he will eventually run out of health because he has to be close range to maximize his damage, and other classes will do more damage to him as he is closer. The best snipers usually take over the game, the best spies & engineers & heavies & pyros do not. That's a class issue, not a skill issue.