According to one of the items that turned up on Google, Ratko was a popular name from the 1940s to the 1960s (Mladic was born in 1943), but since the 1980s has been much less common as a name given to babies. It’s not only Serbian but also found among Slovenes, Croats, and Macedonians.
Makes perfect sense. He was born during WWII. Actually a very good name for a baby born during that war because he was going to have to fight to survive.
"Ratko" is the only Serbian name I know of that deals with war. But there are several Serbian names I can think of that deal with peace. "Miroslav" ("Peace of the Slavs") and "Slavamir" ("Glory to Peace") and the female name "Mira" ("Peace")
War was a constant in the Balkans. Peace was an illusive dream and hope.