Given what we are currently seeing unfold with gas and that oil is a dwindling resource which in some years time will suffer the same "shortage" issues, I feel that while it may not be *necessary* in this very moment to do something about it if you are already addressing both the other 2 sources of energy (Electricity and Gas).
It would surely make sense to lay the groundwork to do the same for oil, with the fore-thought in mind of trying to prevent the same kind of explosion in price of oil we're seeing with gas currently.
I would prefer to avert the problem before it happens, than to wait for the market to reach "ludicrous levels" when we've already had a direct example (and warning) of what will happen to oil in the coming years as supplies (globally) continue to diminish.
Like I said, it seems apparent to me that some level of capping / regulation is required for ALL supplies of Electricity / Heat / Cooking to both curb what is currently happening and to prevent it happening again in the future (with any of the fuels, not just oil)