It makes sense, when someone we cherished is gone suddenly - we want to know what happened. Especially since Moonbin was so young, it makes more sense you want to know. In those cases where you are wondering if you did something wrong as well, we tend to freak out a little bit more as well and want to keep speculating. So, everything you're feeling makes sense.
At the same time though, we will never know everything that was going on in Moonbin's life. KPOP idols reveal so much of themselves on the daily that we can almost forget that they have their own private lives. They choose what they want to reveal of themselves, and in this case Moonbin's family chose not to reveal what exactly happened. We will never have all the details of what happened and our part - so all we can really do is see if we have changes we think we need to make.
All we can do now as fans is take this time to mourn those we've lost and also take a chance to reflect on ourselves in the ways we operate in this cyberspace :)