It's a reference to Abraham Lincoln's first inaugural address:

"I am loath to close. We are not enemies, but friends. We must not be enemies. Though passion may have strained it must not break our bonds of affection. The mystic chords of memory, stretching from every battlefield and patriot grave to every living heart and hearthstone all over this broad land, will yet swell the chorus of the Union, when again touched, as surely they will be, by the better angels of our nature."

Even the most perfect Democracy will only ever represent the wishes of the voters in that country and never those of people who don't have a right to vote there.

Democracy is only less war prone than dictatorships for those situations were there would be large losses, because lots of soldiers coming back home in cofins doesn't go down well with voters.

For situations were there is a huge power imbalance Democracies can be just as war-mongering as the rest, which is why you see lots of military interventions of the US against small countries or countries with ill-trained armies and equipment two generations behind or even, as very heavilly done by the very gentleman quoted in this meme, remote bombing of people in other countries who have no chance whatsoever to retaliate: Obama had no problem whatsoever with remote murdering of people in far away lands because there was no significant path for that to harm him politically (and there wouldn't be even if the US was a proper Democracy rather than the Theatre of Democracy it actually is).

The hypocrisy is how some leaders (most noteable Americans, but far from just them) pass Democracy as good for people in other countries - sure, them having their own Democracy there will probably be good for them, but you having a Democracy makes no difference to them as they don't have a vote in your Democracy.