The answer to this is just simple, greed and selfishness. It is only greed that will make someone invest in a project knowing definitely that the conditions of what they have invest in is not really reliable and realistic. Greedy people are the ones getting scammed in the crypto space in recent time...
It is not only their greed that is causing this, after all most investors need to show some level of greed since we all want to profit from our investments and yet many of us do not fall victims of obvious scams, what happens is that those people have an uncontrolled greed, and we see people like that in the forum all the time, those people that want to obtain 100x profits in a single year by investing in an ico are chasing an impossible dream that most likely will bring them misery instead of money.