As I understand from what they wrote, their plan is to use your finances from buying shares to create ASIC, then mine on it themselves
yes.
but bitcoin community will get cheap asic rigs at the end.
until now it's still risky investment, and I think this is very good timing to say that we are taking risks and a initial higher mining payback is fair as a compensation for the risk.
I think for the BFL customers, as they essentially are taking the risks for the BFL R&D (if BFL fails they will run, as ngzhang speculated), it's fair for the BFL customers to use the rigs first and BFL promise not to mine first. (is there any such promise?)
once the difficulty goes up to a point that selling ASIC hardware is more profitable than mining on it, then they will start selling it.
no.
ASICMINER will be selling the rigs before that, in my understanding.