I am not sure if BitConnect are marketing it as a good deal, they are marketing it as an open source all in one bitcoin and crypto community platform designed to provide multiple investment opportunitie where you can earn interest paid in shitcoins on your shitcoins. If someone see shitcoins as a good investment opportunity, what can you say... Should we make shitcoins illegal or how do we stop people from buying them? Maybe Craig Grant and others are deceiving people but this does not mean BitConnect is. This is like saying the creators of Beanie Babies are responsible for people buying and selling them to each other for thousands of dollars.
Well, shitcoin ICOs are now illegal in China and quite possibly in the US, but that's not the point. Madoff's fund was perfectly legal on the outside, but what he did with the money was a crime.
I don't see how you can claim that BitConnect is offering merely a "platform". They're directly advertising ~1% daily returns on their website. The coin doesn't seem to be available on any reputable exchange, so buying/selling it is not much different from depositing/withdrawing money with any other ponzi. They all "work" until they don't. Masquerading it all with blockchain tokens and convoluted affiliate pyramids doesn't make it less of a racket.