1. This is space. You don't magically stop because your thrusters stop operating. It would be quite irritating if ships with destroyed thrusters would just stop.
2. That would negate the purpose of hatchbreakers.
No kidding but the current mechanics of limpets, hatches and engines disabled makes it impossible to remain profitable as a pirate. So I'm forced to chase until they stop or kill them outright, which I do if I need to. If we want to see less chasing and less killing, as most pirates will agree, my changes are reasonable.