Misguided pedantry

James Taranto today says,

We take the pedantic view that the 1990s consist of the decade from 1991 through 2000.

Say what? Look, I know he's looking for some parallelism with the fact that the 21st century A.D. started in 2001, not 2000, but there's no direct translation to "the 1990s" starting a year late. The 1990s were the ten years beginning with the digits 1, 9, and 9. That where the term comes from. It's absurd to think of the year 1990 being excluded from the 1990s.

Think of it this way: "The twentieth century A.D." and "the 1900s" are not synonymous. The former comprised the years 1901 - 2000. The latter comprised the years 1900 - 1999.

UPDATE: If you wanted to call the years from 1991 - 2000 "the tenth decade of the twentieth century," it would sound awkward but be correct. But that's not the same as "the 1990s."