Not only not vertical, but apparently not parallel.
The shrouds don't bend the mast, if I get your meaning.
They grab the wind power and send it down to the hull, which uses that power to drive forward.
The drawings show the set up at rest. Under sail, blowing along at 20 knots, those shrouds are singing like Callas and the mast is moving around in scary ways.
That rig, with sail booms including jibs, makes setting sail on the deck like tucking and rolling through a convoy of UPS trucks.