Of course we do. The Gulf is said to leak 2000 barrels a day naturally.
Technically a truism, but is there someone other than you by whom that is said?
Some natural leaks in the gulf of California are even bigger.
In 1995, the Smithsonian was saying that natural seeps globally totaled 62 million gallons/year which is about 4k barrels/day. In 2000, NASA put a number around 1.5k bbl/day on Gulf of Mexico seepage, with a methodology that couldn't fully exclude human-caused leakage but only included the northern GoM. The 2003 NRC "Oil in the Sea" report put global seepage at 600k tonnes/year which is about 12k bbl/day, and extrapolated the NASA GoM seepage data to 140k t/y for the whole GoM, or 2.8k bbl/day.
My point is not that 2k bbl/day is a wrong number, but that (as that NRC report made clear) natural seepage numbers are only a little more than order of magnitude estimates, and at best have only one significant digit. That is largely because the nature of marine seepage is such that it generally does not cause noticeable effects. The spread of those few thousand barrels per day across the whole of the GoM has led to the development of ecological systems that can degrade that widespread and essentially continuous input of oil that is seeping slowly in any single location and doing so through porous areas in sedimentary deposits that have effects on what reaches the open water. A well blowout is fundamentally different because the oil is spewing out of an open channel to a sub-surface reservoir which in most cases worth drilling has a non-porous cap layer above it. So even a partial well blowout like the current one brings both a gross carrying capacity overrun with more "oil" coming out in one place than the whole GoM system normally handles and a qualitative difference in what that "oil" consists of.