I read your 3 articles and they are narco related, the policemen shot happen to be "municipal" police and they are normally controlled by the local narco gang, a rival gang that wants the territory is sending a message to the local narco gang and the municipal police force.
On the other two items that you refer to they are also narco related, if you check where the "colonias, mentioned are you will see that they are not in the tourist area, as for the beaches, some drug shipments arrive by go fast panga, they even reach Coronado, La Joya and Encinitas beaches in California.
As long as you have no buisness with the narcos you are safer than any Mexican in Mexico , you are a "gringo" and that is something they do not want to mess with, the isolated robbery or "asalto" to a gringo is commited by the local punk.
One reason that the gringos are left alone by the narcos is that a murder of a turista brings the federeal government police and the Mexican Navy Marines,the narcos do not want the attention of the government at all, bad for buisness and the Municipal police and the State police are bribed by the narcos good for buisness.
If you are concerned with your safety, you are safer in Mexico than in the USA even safer than the legitimate Mexican "turistas" in the USA.
navegator
