Because it's not a WMD. As other posters have already pointed out, the uranium in question is depleted. It may emit enough radiation to register on a sensitive Geiger counter, but that's about all. The radioactivity wouldn't kill anyone, and it certainly would cause any "mass destruction".
Too many ignorant people get all hysterical over anything which is the slightest bit radioactive, irrespective of the true danger or lack thereof. Let's not encourage such hysteria by deliberately mislabeling things.
Why isn't this leading story on all the news channels?
Because it's not overly newsworthy.
Why don't we see the Dems apologizing to Bush???
In this case they have nothing to apologize for.
Yes, these were just rhetorical questions.
Not really, since the implication in each case is that your answers are wrong.