He was retired, sure, but this is a denial of his entire career, if not his life’s work (I can’t speak to how much being in the military means to him).

How would you get a surprise in the mouth when you’re stuck headfirst in the washer?

or why only those with dragon blood even attempt to say dragon words

That’s not a requirement. Ulfric is right there. The Greybeards are right there.

Being Dragonborn just lets you eat dragon souls to gain literacy.