He's no different than Colin Powell who went to the UN to lie about weapons of mass destruction. Assad didn't gas his own people, the "rebels" did - the "rebels" that the United States supports. There are no "rebels", they are simply terrorists funded by the United States through Saudi Arabia.
"We need to be providing defensive arms to the people of Ukraine"
Why provide arms unless you support war?
"I'm an internationalist I'd like to see our troops dispersed through the world only at the directive of the United Nations."
Why send troops around the world...Troops are meant for war?
I believe that John Kerry uses peace as the narrative when discussing resolve with other nations. Although John Kerry served in the military (he fought in the Vietnam War) and although early in the 2000s he urged President Bush to aggressively attack Saddam Hussein, he urged the president to use diplomatic solutions to resolve the political issues at hand. Most recently, John Kerry worked with the U.N and with Iran to resolve disputes between the United States and Iran regarding Iran's nuclear facilities. He stressed that he would not attempt at warfare to settle the differences. John Kerry is much like John McCain; both are war veterans that have seen the battleground and strive to prevent future wars from happening.
John Kerry is a Democrat, which makes him fundamentally not a warmonger. This isn't to say that he does not accept war when necessary, as most politicians do. However, if John Kerry were a warmonger, then he would be a Republican. This isn't to say that Republicans are warmongers, but that one who is a warmonger would not get along well with the Democrats, but could fit in with the republicans. A warmonger is someone who provokes war. There has never been any evidence that Kerry would like a war to take place. He does have a military background, however he has not shown any public intentions of going to war.