"COWARDS RETURN TO THE MOON" is meant to stigmatize risk adverse, misconceived proposals which suggest Mars mission systems and equipment should be tested on the moon prior to their use on Mars.

"THE MOON IS RIDICULOUS" means the moon is unprofitable, foolish, silly.

"I LOVE NEA/MARS DIRECT TUNA CANS" means: I love Near Earth Asteroids and small inexpensive compact habitats (jokingly referred to as food canisters because of their size).
http://en.wikipedia.org/wiki/Near-Earth_object#Near-Earth_asteroids

"MARS TO STAY" means once young 35 year old astronauts finally arrive on Mars they ought to be expected to stay there for 30 or 40 years. After technology has advanced and we have established a permanent settlement on Mars these original astronauts would then be given the opportunity to either retire on Mars, continue traveling, or return to Earth. Initially astronauts would be expected to stay on Mars.http://en.wikipedia.org/wiki/Mars_to_Stay

"TRAITORS RETURN TO EARTH" means astronauts who return to Earth before establishing a self-sustaining settlement have betrayed humanity, failed to fulfil their moral imperative to settle Mars, and criminally impeded our quest to become a spacefarring species.

"WHAT WOULD ZHENG HE DO?" is meant to ask which human spaceflight missions Zheng He would recommend international space exploration enthusiasts should advocate -- especially if a lunar base only two days away is merely one scientifically illiterate or populist president away from being closed. http://en.wikipedia.org/wiki/Zheng_He