You are only ever passing in true or false here, so a toggler isn't really needed. You're being explicit, so you might as well call something explicit.

I suggest putting the functions bindKeyDownListener and unbindKeyDownListener onto _this and calling them directly inside here instead of a new function that has a potential code path that it can never really split on.

Also I am curious if a function like this, that you can add and remove would stop it too.

function stopPropagation( e ) {
  e.stopPropogation();
}

// interaction start
window.addEventListener( "keydown", stopPropagation, false );
// interaction end
window.removeEventListener( "keydown", stopPropagation, false );

Not tested, should work though.

This way it is a stand alone thing and doesn't require a wire into butter.