Agreed. We should not subsidize.
But do they need to be? They are surely less emissive than driving a truck, let alone an oil tanker across the ocean.
All the same, it would be a damper on OPEC price raising, because they dare price their oil so high that refining tar sand would become more economical.
But most likely to be safer than alternative means of transport, and greener. Trucks and tankers can have massive spills.
But oil prices today reflect anticipated future prices to restock inventory. This is why there was a huge price hike in petrol in the USA before the Putin invasion: since petrol outlets knew that Biden was sabotaging US oil production (apparently oil from anywhere else doesn't pollute as much), they realized that they would be facing increased costs to resupply the pumps. So they raised current prices so they could afford to restock with the scarcer oil in the future.