Why does JSHint swear?

Question

Sublime Text

Swears at such code

function setActive(state = 1, exception) {

}

They say you can not specify default values, although I set ES6
.jscshint

{
    "esversion"     : 6,         // {int} Specify the ECMAScript version to which the code must adhere.
}

Moreover, I cannot understand why he swears at such a returned object