It also could be a strategic positioning to put them in the driver's seat as the swing producer instead of Saudi Arabia. As someone recently said to me - If the Saudis are pumping flat out, then anyone can cut back and become the default swing producer. Thus you hold the keys to the price and save more for tomorrow. Cutting back production is exactly what I would do if I were Iran, Venezuela or Russia.
If they can think long-term, you're right that cutting back will optimize revenues. But can these countries really afford to reduce today's oil revenues for a rosier long-term? I'd bet on short-term thinking.