"Didn't Hillary call the entire Marine Corps "extremist" once?"
She may well have...but I think that the incident you are recalling involved
some female appointee who was part of a group trying to re-engineer the US military.
I can't remember the shrew's name, but IIRC, some USMC officer made some sort
of "thank you maam', we are extremists" remark soon afterward.
INSTANT GOOGLE SEARCH UPDATE:
here's a link to an article on the incident by Rowan Scarbourough
(of The Washington Times...and author of the great new book "Rumsfeld's War")
http://vikingphoenix.com/politics/Election2000/Issues2000/NationalSecurity/lister08.htm