Sometimes the simplest answer is the correct one.
There was never an accident with tail icing on the 737 so definitely it is not the simplest answer. Yes, simplest answers are usually closest to the truth, the simplest answer is totally mishandled go-around, it happened numerous times and it actually happened in Kazan, Russia barely 2 years ago. And all the symptoms were practically identical. Tail icing doesn't make sense for one simple reason - it would be at its worst during the approach with all flaps fully extended, not the go-around.