Orthodox Christians believe that only one person of the Trinity became incarnate in Christ, so whatever happens during the incarnation, God the Father and God the Holy Spirit are unaffected. Moreover, they believe that even while God the Son was incarnate, he still performed his cosmic and divine functions, whatever they may be. And finally, they believe that when not incarnate, God is outside time. So it's not like God is sitting there watching the world, then suddenly he's inside Jesus for a few years neglecting everything else, and then suddenly he's back to watching the world again. Rather, he timelessly watches the world (from his perspective), which means that at any given time (from our perspective), God is watching the world - and this applies during the period of the incarnation just as much as at any other time. Because it is true even during that time that, timelessly, God the Son is watching the world, even though it is also true during that time that, temporally, God the Son is incarnate. Moreover, on some models of the incarnation, God the Son remains atemporal even when incarnate - all that happens is that he becomes united to a human being, but the human being is temporal, and the Son remains atemporal. Peter Abelard had a model of the incarnation like this and Brian Leftow has defended one in recent years.
But of course it's much easier to mock the doctrine if you don't bother to find out stuff like that.