Because 90% of what has "bitcoin" in it IS scams or stupid ideas.  Starting with attempts to convince the unwary to buy bitcoins "because they will go to the moon" or "a hedge against inflation" etc..

For example, I  already mentioned a couple of days ago that student of mine who had been offered to join some GPU-based bitcoin mining enterprise.

I have to check who is on the board of the Brazilian Bitcoin Foundation.  I would almost bet that the creator of the BitcoinRain ponzi is there.