Forgive me if this sounds like a half-cocked rant. I'm really tired today but felt like I needed to say something.
I saw that the site Refinery 29 is launching a site for "plus size ladies size 10 and up." My reaction, instead of being glad to see that, is that I am decidedly not OK with a 10 being considered plus sized. (Note: all clothing sizes I refer to are U.S. measurements.)
It's not because (as someone actually said to me on Twitter) I think 10 is "normal," which, of course, indicates that plus sizes are a deviation from that. It's not because I think "plus size" is an offensive label or that it somehow damages the otherwise-socially-acceptable size of 10. It's because plus sizes need to keep aiming up, not down.
As it is, the smaller end of plus sizes -- currently the standard is to start at 14 -- get the bulk of the good stuff. There are more options, more representation in models (though plus models are still overwhelmingly too small), and more mainstream recognition. Once you pass, say, a size 20 or 22, you're in a proverbial no-(wo)man's land.
I can only sort of speak from experience on this. The largest I have been is about a 22/24 (and the smallest in my adult life is about a 16), so I have never really faced what it's like to be someone who needs a 28, 30, 32, or larger.
What I experienced is that once your size has a 2 in front of it, there is an immediate drop in options. Lines that brag about how they are making plus sizes and are suddenly oh-so-accepting-and-awesome don't really cater to anyone high up there. When Forever 21 first introduced plus sizes, they included 1X and 2X. That's not exactly much of an extension, especially when you consider that they also run small. Now, they have corrected themselves a little, going to 3X and adding in more styles. But that still excludes a lot of people.
So my reason is that including size 10 in the line of plus means the border is even lower, so women who wear sizes higher than 20 will be considered even farther outside the threshold between straight and plus sizes. In a world where lines already cater to the smallest plus size possible, the last thing we need is to have that size be even smaller. It's not because I think being called a plus size is a bad thing. It's because too many other people do, so to be further outside the so-called norm will be incredibly damaging to a group that is already too often excluded.