I would distinguish two different cases:
1) You were using legit service just for common purposes, like coin exchange that had been "hacked".
2) You were greedy and would like to magically multiply your BTC (ponzi, IPO etc.) and then got scammed.
Of course, there is no excuse for scammers. But as long as we can do nothing to punish them, the only line of defence is to make right choices.
You didn't? If you need to get some practical knowledge in this matter, you have to pay