I don't know what is definition of scam, but details (including the fact that they are keeping the tokens) were publicly announced. And every investor should make good research about everything about the project they are investing in to.
Now it's up to STASH team how they will decide about the future of this project.
Agreed.. the whitepaper does lay out exactly what's going happen.. the info is pretty bleak, frankly, in that they are planning to develop something that they 'hope' the community will actually implement and then hopefully that community will honor the tokens that were sold during the ICO. It's pretty much a guaranteed loss, but they were upfront about it.
ICOs are easy to invest in, but that doesn't mean the people behind it are the people you would want to give your money too.
As with any ICO, always do your homework prior to investing, after all, its your hard work money. Also agreed, STASH did make it upfront that this project is also community driven, as stated in STASH white paper.