How did they get to the SR-latch with 2 NOR gates?
Generally, an RS latch will be used in situations where both inputs will never be active simultaneously, and thus the behavior of the circuit in such cases won't matter.  The effect of the extra "or" gates is to make it so that when both inputs are true, both outputs will also be true; in their absence, having both inputs be true would force both outputs to be false.  If one needs the outputs to both be true when both inputs are true, then the extra gates will be required.  In cases where it would be acceptable for both outputs to be false as long as both inputs were true, however, the OR gates may be omitted (simply wire the outputs to the input that came from a NOR gate) since they do not affect behavior in other cases.