No WMDs, but we're worried nonetheless!?

Robbins on NRO does an excellent job debunking the leftist conspiracy charges based on the material in the "Downing Street Memo". It should also be noted here that the extreme interpretation of this memo on the left is that there were no WMDs and that Bush & co. were drumming up the entire thing out of whole cloth. However, if you read into the memo you notice that the same US sources for the document are also concerned about Saddam using WMD:

On the first, CDS said that we did not know yet if the US battleplan was workable. The military were continuing to ask lots of questions.

For instance, what were the consequences, if Saddam used WMD on day one, or if Baghdad did not collapse and urban warfighting began? You said that Saddam could also use his WMD on Kuwait. Or on Israel, added the Defence Secretary. source

So, the question is... if Bush & Co. were simply manufacturing the Saddam threat why are they worried about fictitious WMDs in the same breath? I think logic will prevail here.