Letting Voters Decide Is Mudslinging?

Since when is suggesting it is up to voters to decide if a candidate’s claims are valid slinging mud?

Obama has cited that his youthful experience, "I spent four years living overseas when I was a child living in Southeast Asia,”…… “A lot of my knowledge about foreign affairs is not what I just studied in school. It's actually having the knowledge of how ordinary people in these other countries live."

Responding to such claims of experience Hillary Clinton responded, "Now voters will judge whether living in a foreign country at the age of 10 prepares one to face the big, complex international challenges the next president will face. I think we need a president with more experience than that."

Edward’s spokesman Chris Koninis  response to this was “"Now we know what Senator Clinton meant when she talked about 'throwing mud' in the last debate. Like so many other things, when it comes to mud, Hillary Clinton says one thing and throws another."

The above quotes are from an article(?) I found in the 11/21 online edition of the Washington Post at http://www.washingtonpost.com/wp-dyn/content/article/2007/11/20/AR2007112001880_2.html

Granted, Clinton did add her own opinion, but is that slinging mud? Apparently the Edward’s campaign does not like the idea that Hillary is entitled to express her opinion or that  it is up to voters to listen to candidate’s claims and decide for themselves if the claims are valid or relevant.