The tagline for the article, "That's a fact" is ridiculous........consensus doesn't determine facts, and this is a far less commanding consensus then on say, evolution or the Earth being older than 6000 years old.
Also, since the thesis was guns make society LESS SAFE, not less safe vs more safe, the "consensuses" are 72-28, 64-36, 73 vs 27, 62 vs 38, and 71 vs 29. These are hardly unanimous verdicts.
Furthermore, Freaknoomics did good research on this and found a house with a swimming pool is far more dangerous than one with a gun.
I do feel like the left tends to grab on to "consensus" as some buzz-word to avoid actually debating issues at times.
Here's a good source to learn a little bit more about the pro-gun rights side:
http://www.cato.org/publications/commentary/gun-control-myths-realities