Based on the language and "cartoon violence" as well as depicted drug use dota 2 would very likely get a M rating and would get a minimum of T, the only reason it isn't is because it's entirely online and as such not rated.
Not a kids game
every character, every ability, and every item has a name, a description, and in the case of the former 2 a visual representation on screen. all it takes is a single instance of it for it to get that tag in its esrb rating.
Not a kids game