Oh well if someone who had alot to gain estimated there were 100K people who am I to be skeptical...
And the media has nothing to gain from playing down pro-peace stories? Of course they do, they've long decided to marginalize the anti-war movement, and that there best interest is aligning themselves with American foreign policy... it's is very rare to see the American media really questioning American foreign policy.
As to your AP quote, there have a been widespread reports that the AP number was extremely inaccurate. Personally, from all the articles I've read and discussions I've had with people who were at the protests, I believe the numbers were in the tens of thousands. But heck, neither of us were there, the media barely reported on it, who are we to believe?
Go ahead and believe the AP, just like we all believed them when they said there were Weapons of Mass Destruction in Iraq.