I have that feeling too. More information is needed before can say for sure wheither the shooting was justified or not but this teenager was certainly behaving badly.
Ringing the bell and running is one thing when you are eight and it is daylight. It is quite another thing when you are adult sized, it is the middle of the night and you stick around waiting for the owner to come out.
Either they were incredibly inept at "ding-dong-ditch", or they were incredibly inept at "home invasion and burglarly".
Judging from the reaction of those who claimed to know him, I'm inclined to beleive the latter. Note that his "friends" here placed no responsibility with the perp, and totally blamed the homeowner (at least in the posts I've read). Also, they have made references to how popular and well-liked he was, which is irrelevant to the events of that night. Furthermore, they have made personal insults at those who disagreed with them. All this leads me to believe that you have a bunch of kids who think that society owes them something and that they can get away with anything.
However this situation turns out, Darwin appears to be the clear winner.