Just give the Thalmor a taste of their own medicine.
Mass genocide is always the solution of getting rid of people we don't like. Wonderful.
AFAIK the Thalmor were defeated in Hammerfell. I bet it was because Redguards heavily demoralized them by fighting naked, showing them they're not the best and biggest in everything. I'd just repeat the process and send an all-Redguard army to fight them in any province they smell into that's not Summerset.
Have the Thalmor defeated by the people that they view the most Inferior.
get an Army of Khajiit, Argonians, and Imga to put them in their place.
See how well they can suggest Elven superiority then.
"Us Altmer are not arrogant.
We are just aware of our superior intellect, physique and culture.
Living in an imperfect world as a beacon of enlightenment has, after time, an effect on the psyche.
What is often mistook for arrogance by the lesser races is in fact the air of confidence in ourselves we exude, our natural recognition of empirical facts.
Of course, jealousy is a terrible thing and that is why the lesser races often mistake us for arrogant.
It's understandable really, to do any less would harm their own self-image.
No-one likes to acknowledge inferiority, even when it is the truth.
So I call on my golden brothers; feel pity, not loathing, educate, don't berate.
When we lift up our lesser brethren to the glorious heights of our holy endeavour, they will experience the light that shines of the crystal tenets, they will open their eyes and come to love us." - Merari