BS.
In far too many states, including California, home of 20% of American citizens, that's still true.
The BS is in the writer's statement that the 12 round mag was "created for law enforcement." The 12 round mag was "created" by a SIG gun designer, for SIG gun users, to maximize the number of rounds which would fit in the envelope. The "reduced capacity" 10 round mag was created for Americans forced by legal fiat to accept less than the standard mag capacity.