Also, Torygg didn't have a choice. He knew he was going to die if he accepted, but if he declined, Ulfric would use that for his Stormcloak campaigns and he'd never hear the end of it, plus he'd be dishonored and viewed as weak. So either way, Ulfric was going to benefit from this deal and placed Torygg in a tricky spot. He just randomly goes in to Solitude one day and says "Death or dishonor?" You can't really hold Torygg's melee skills against him, he didn't have any knowledge of the Thu'um and not all leaders are made out for combat. If combat prowess did matter in politics, then Tamriel should be a military state and Tullius should be Emperor, not Mede.
Welcome to politics.
And yet Roggvir is still yet not guilty of a single wrong.
The king was weak, stupid and without a brain. He brought his doom on himself by allowing Ulfy in the city to begin with.
Had he declined, the moot would have been called, yet there would have been a chance he'd be recalled as high king. But the fool took the worst possible option.