If they would offer a refund policy and in July BTC goes to 100$ then everyone will refund and if the money are spent on components they won't be able to refund everyone. Every company is saying that they don't guarantee customers ROI.
The refund policy to which I refer is only if they don't deliver on spec and on schedule. People would not have the option of a refund just because bitcoin price goes down.
Everything you said about shady and unreliable vendors in the bitcoin mining space is likely true, but that doesn't change the fact that repeatedly making promises without putting anything of substance behind them is cheap talk, and is very different from making a binding and substantial commitment to the customer.