Your stat shows that (i) Myanmar's citizens were not unarmed and (ii) privately owned firearms were more widespread in 2007 when the country had been under the control of an autocratic military junta for decades than in 2017 when it appeared to be transitioning to semi-democracy. Myanmar is certainly not well functioning, but it is also certainly not an example of effective gun controls, or an example of widespread private firearm ownership preventing autocratic regimes from doing what they like.