Every ICO has it stated how they deploy their coins and you shouldn't really invest in the ones you're not comfortable with. I understand that you didn't search or read and you'll be careful in the future but the title is a bit sensationalist because it sounds like someone stole or tricked people when usually this sort of information is right in the whitepapers or on the websites you invest in.

As to why some do it one way or the other, it just depends on how the devs choose to build their contracts/ICO/business model...