Ah, media-world, where women have no waist and huge breasts and men have washboard abs and arms the size of cannonballs.
Anyway, there's a standard for both males and females in the fashion industry (though it varies by country, the US is actually much
better than Europe). VS does not subscribe to the standard, preferring models to have more weight than the standard (therefore having more assets with which to push the product), which is what they mean.
22 or above is 'plus sized' in the US, by definition. 12-20 is 'full figured', which is only considered above average in the fashion industry (the actual average for US women is 14). The rough equivalent of 12 is, however, 'plus sized' in Australia. In Europe, 'plus sized' starts at the rough equivalent of 10.
By the way, a lot of companies that sell clothes actually have been upping the size of their clothing without changing the label.