Mob mentality. Everyone heard about a great thing and they want it asap. Unfortunately, this great thing is unreleased code and not fully tested yet so people who don't know exactly what they are getting into are willfully risking their systems because they either don't understand the huge risks, or don't care. Some people have money and systems to spare, others assume they won't have any problems at all.
I'm also sure there are some that simply don't understand that a brick is unfixable by the common user.