A pilot should know his capabilities, and those of his aircraft, before departure. He should take them into account in deciding whether to depart, in selecting a route, and in balancing risk versus the benefit of completing the flight.
Of course. Pilots certainly have that responsibility too.
A pilot restricted by his qualifications, or the aircraft he flies, must bear those restrictions in mind before setting off; the restrictions are not a cause for catastrophe, though poor decisions or bad judgment may be.
It's not quite as simple as that. Regulators, who are effectively safety managers, also have responsibilities. In my opinion, there is reason to question the efficacy of any regulation that encourages a pilot to adopt a plan that is legal but less safe and reject one which is safer but prohibited by regulation. The balance of overall risk is often difficult to assess in issues of training and licence privilege, but that doesn't invalidate the question.
If the authorities make the instrument rating more difficult and expensive to acquire than is justified by safety requirements, then those authorities must take some of the responsibility for accidents where pilots without valid IRs have come to grief in circumstances where they were capable of executing the flight safely but unable to do so because of regulation. On the flip-side, those who argue for an easier IR might bear some responsibility for the accidents involving pilots who attempted to exercise the privileges of an IR but who came to grief because of insufficient training.
This accident may or may not be relevant to that debate. It may be that the pilot was licensed to fly above the weather but chose not to do so. It may be that the pilot would have come to grief anyway -- though I stick to my assertion that a flight over the weather on a day like that was vastly lower risk than trying to go through it, and that that risk was reasonable in the circumstances of the flight. It may even be that the pilot elected to fly above the weather but some failure brought him down anyway. But this accident may also offer useful evidence to inform the debate that responsible safety managers should be engaged in.