Cheating = When you get an advantage through other means which allows you to do/achieve something which otherwise you would not be able to. The definition of Cheating has nothing to do with the ease of its exercise.Well if you ask me, if somebody shows their card to thousands people voluntarily, and if I look, that is not cheating.
And it is not related to definition of cheating, it is more your subjective interpretation.
If you were writing an exam and the answer to the questions was kept in a notebook beside you, and the professor asked you not to look but cannot monitor you - would it not be cheating if you looked. If someone kept his money outside their door, would it not be stealing for me to take it?
Similarly, if I stream snipe someone to get information which results in getting an unfair advantage over them, it's cheating by definition.
PS - You can argue that it's silly to keep your money outside the door and then cry about theft. But it's still stealing. Similarly, about live streaming. It's silly to livestream your tournament games with 0 delay, but that doesn't mean it's not cheating when opponent checks your stream to get information.