I don't really see the big deal... I mean, you seem to be majorly overreacting.

Hypothetically speaking, if I were you, I probably would be a bit 'huh?' if someone didn't credit me. But I'd get over it. (very quickly.)

Are they charging for this sim? No, not that I can see.
And despite the fact that you are not credited on the main site, I'm sure a small PM or email would clear the issue right up. So instead of getting butthurt on here, why don't you contact someone on the site? I'm sure they're not going to try and bite your head off if you ask for credit. It's not as if they're passing your work off as their own; your mark is still on the texture file, after all.

Anyway, you should be flattered that your stuff is being used on other people's sims, not offended.
And your creation was pay, right? Well then, the folks at Bluewater are within their right to redistrbute your files, seeing as you shouldn't have been charging for those files...

God, I feel like a bitch; but you've got me all riled up, kthx.  (Anyway, it's not a personal attack on you. Just trying to be a little voice of reason, okay?)

*giggles incessantly*
Good lawd, that stuff is fucking horrid.

Maybe they were just so rabidly enthusiastic about charging moneys for their shit that they made a mistake... *ahem* 

Wait a minute; have they changed something on the front page?

It's down at the bottom of the main page, below that flashy 'click here to join' sign.