I always think this about the soda taste tests, where people say they prefer Coca-Cola, but then prefer Pepsi in the blind taste tests, as if they couldn't taste the difference. They don't taste the same at all...
The people who picked pepsi got swag, the people who picked coke did not. They didn't hide this at all, they would yell that pepsi was the winner every time someone picked it, and gave them cool stuff in front of everyone.
The fact is some people can tell the difference and some people can't. Part of it is training if you devote some time to learning the differences in taste then you will gain some skill. I drink both of those colas roughly about the same amount so I've become acquainted with the taste differences.
Part of it is genetics some people just have more sensitive palates than other. I do in general have a more sensitive nose than many of the others I know so that may be part of it as well.
I would wager though that the majority of the population have neither trained nor have the sensitivity to tell the difference between a lot of things.
I suspect something similar is going on with other taste tests. Different people are sensitive to different flavor profiles.
Pretty much a moot point since I don't drink much pop to begin with...
Those taste trsts normally give small sips of the drink. That changes the way you drink it, and that affects the flavour.
They also tend to use colder drinks which also affects flavour.