I believe that the coins can be purchased from EA directly (in addition to being slowly earned via gameplay). The "black market" is black because it's against the TOS for the game, and essentially means that EA loses money when players get their coins from that market rather than from EA (there are apparently dozens of sites out there). If the black market undercuts EA too much then EA loses more sales, and flooding the black market with millions of ill-gotten coins likely leads to undercutting.
This is just based on limited research... maybe an actual player could clarify. So is EA losing money? I would guess that the $17M could represent lost coin sales, since somebody paid those guys for those coins that they may otherwise have bought from EA. At best it is unauthorized use of their servers or possibly a breach of TOS, which I guess in the US is equivalent to whatever crime the writer of the TOS wants.
From a player point of view, having automated generation of in-game currency leads to market inflation and essentially leads to items being priced out of your average player's range. However since EA is selling the currency themselves and making the goods scarce (it seems that certain player purchases used to be auctioned) I don't feel bad that someone is pissing in their pond.