Yes he could have better prepared himself for the stream but that's besides the point. You can't justify your actions nor the behaviour that you exhibited at the time of the stream. You actually took it upon yourself to watch the stream, located his character and murder him, that alone says something about your personality and the lack of respect for those who are trying to get the game noticed.
Yes crimes & drama is very well suited to this game but there are times when its not appropriate, people must to allowed to give a welcoming demonstration of the game without the chance of it prematurely ending because you feel that the world should know at what you do best.