Hearing the comments from this community should really give you an answer as to why it happened. If you are looking for blame, it's the community. If you are looking for more blame, it's Bungie. They developed a game based on grinding and farming to get the chance for the best gear through RNG. They still omit matchmaking, giving randoms God power to kick anyone they choose because we have to trust randoms. The community is to blame, but Bungie quite obviously has created this vile community through naive thinking on gameplay.