There is clear evidence of people buying games from seeing streamed footage of them. Twitch is just another media outlet like any other. By using your logic, people watching Let's Plays on YouTube would just not be bothered to buy the game being played, and would just watch the LP. And yet, I and many others have bought new games we would not have found otherwise. Streaming is just the exact same thing, with the exception that it's live.

Just because you dislike the format, it does not give you the right to call people stupid or lazy for liking it.