I went to Tulum in late December 2014 and early January 2015. Felt perfectly safe. I take the US dept. state warnings with a grain of salt, lots of them are overblown, especially considering some cities in the states, I mean, come on...Take normal precuations and you should have no issues. Every place in the world has some kind of issue, after all. I also think it is unfair to judge a country based on issues experienced in parts of the country. Ya, Acapulco is known to be unsafe but that does not mean you should not visit Mexico. That is like saying "Detroit is unsafe, I won't visit the USA."
Also, that article gives stats for 2017 but official FBI stats for the US are not available for 2017 so I highly doubt those are official stats.
Really, I tend to love to hike and explore and do active things but mostly I just relaxed for the few days I was in Tulum, beautiful beaches. I also went to Playa del Carmen and Cozumel and some ruins and other natural beauty areas a little inland from Quintana Roo. Food is good and cheap though be very picky with street food. I mean, part of the allure of a country like this is indeed the street stalls and some of it can be awesome but some of it...eeep, stomache issues. So observe, check to make sure it is fresh food and enjoy.
I intend to visit Mexico again this summer 2018.