If it were classified as a disease, what changes should that bring about in how society manages it? Some pay laws? Affirmative action in certain situations? Not making fun. I'm genuinely curious how you think a "diseased" status could help you and people like yourself.
Anyway, I believe that wen there's a person, there's a way to aesthetically bring out the best of what they've got, barring only extreme medical situations (500+ pound morbid obesity, entire face blown off, being a headless ghost, etc, etc). It may be tough to find: what's in style will not flatter everybody, and that counts against no one.
I hope the above does not come off as dismissive. I in fact do believe it to extremes and ground out my own style under pressure.
4w5 6w7 1w2 sx/sp ⏩ ISFP
RLOAX (don't do it) ⏩ Melancholic Hufflepuff
A lonely island where only what is permitted to move moves, becomes an ideal. Jung
It is, I'm sure, a disadvantage, but it's too subjective to quantify. It's also not a disease. A disability might be closer, but quantifying it really would be difficult. At this point, you'd have better luck getting that status from mental illness resulting indirectly from ugliness and I think it realistically could, but doesn't have to. There are other factors that influence how debilitating it is.
“There are two novels that can change a bookish fourteen-year old’s life: The Lord of the Rings and Atlas Shrugged. One is a childish fantasy that often engenders a lifelong obsession with its unbelievable heroes, leading to an emotionally stunted, socially crippled adulthood, unable to deal with the real world. The other, of course, involves orcs.” ~ John Rogers
It's pretty possible to make up for ugliness with personality and a decent shape. Weeks ago, I read that Ronaldinho lost his virginity when he was just 13 (in my hood, that's a win), and has gotten laid a lot since then.
Oh, money also helps.
The way you carry yourself also matters a lot. Anderson Silva looked fugly when younger:
Nowadays he looks somewhat attractive even:
A man builds. A parasite asks 'Where is my share?'
A man creates. A parasite says, 'What will the neighbors think?'
A man invents. A parasite says, 'Watch out, or you might tread on the toes of God... '