Please check your facts before posting. BP has NEVER operated the rig - nor for one day. BP hires Transocean to provide virtually turnkey services to drill wells. In exchange it pays Transocean around $500 K a day. Transocean owns the rig, operates the rig, mans the rig, owns the equipment (including the BOP) and is responsible for the processes and procedures onboard the rig. It can hardly be described as BP's accident.
However, BP - as the operator of the drilling lease (not the rig - don't get confused) - has a statutory responsibility, under OPA 90 regulations, to clean up oil that is spilled and pay for the consequences and natural resource damages.
The only impression that is wrong is the one you have formed - along with millions of others who lack curiosity and jump to conclusions.