Facebook does indeed keep your email list once you've uploaded it - but just doesn't like to admit it.
Really! To find out that they do this, go to the "Suggestions" Page, click on the tiny link in the tiny text note: "Facebook will not keep your password Learn More" (Really, it's teeny)
If you click on that, the window that opens also tells you that it keeps your addressbook data too: "We may use the email addresses you upload through this importer to help you connect with friends, including using this information to generate Suggestions for you and your contacts on Facebook"
Not that I mind that it tells you about not keeping your password, mind - but slipping in that it will also keep your uploaded contact data is at best accidental obsfuscation and at worst, straightforward corporate nastiness. Worse: There's actually an implied suggestion that they are not intending to re-access your data in the statement that they don't keep your password.
Once you have found your way this far, however, it does also give you a link to an opt-out mechanism. Clicking on the button takes you to http://www.facebook.com/
Searching the help system for explicit help on the Friend Finder points you at information on the Friend Finder, but gives you not a sniff of any of this, by the way.
So this looks like the most likely solution - and we'll see if doing that has any effect. Of course, while memory is a funny thing, I'd still swear that I didn't see those two names in the half-dozen suggestions Facebook came up with when I uploaded - or that those names appeared in my uses of F'Suggestions' since then until today - and as those names are meaningful to me, I'm pretty certain to go *boink* upon seeing them in a odd context, just like I did today in fact.
So half a solution, perhaps. :/