Both types of people are physically unattractive to the majority of women. Short is a huge blow, but being an undesirable minority makes these people incel-worthy. No matter how much self-improvement they do, they will never have any sort of sexual success (multiple relationships, casual sex) and will have to settle for the most unattractive women out there via arranged marriage or terrible dating opportunities (obese, single moms, facially disfigured)