Like any get-rich-quick scheme, bitcoin scams thrive on the gullibility of its victims. Just because it's a digital currency doesn't mean you can acquire wealth quickly.
Of course there are always people who will take advantage of people that are new to this industry and do not know about how things works around here. This is natural not just in this industry but in all sorts of industries here in the world. The only defense people can have from these things is proper knowledge. Nothing more, nothing less.