What I meant was that as nearly everyone finds vomiting very unpleasant, why are more people not afraid of vomiting/sickness bugs
Because they're nothing to be afraid of.
They're unpleasant, but generally in the wealthier parts of the world, they don't mean you're about to die. They mean you're going to feel unwell for a bit and then you'll start to feel better again.
In places where there are more serious infections or the mortality rate is higher due to assorted circumstances, people aren't phobic because, frankly, they've got far more to worry about with Malaria, TB, childbirth, starvation, malnutrition, war, civil unrest, Ebola, rabies, drought, locusts, Measles, Polio, Tetanus, Cholera, Dysentery, HIV, standard bacterial infections with no access to free medical care and a shit ton of wild animals that are a lot more dangerous. It's just another thing that can happen. They don't have the luxury of being able to fixate upon one symptom and chances are that they have neither the money or the infrastructure to be able to do much about it in any case.
Emetophobia is very much a condition of privilege. It's because we are safer that it can become seen as a threat to the comfort of our lives - the people who are emetophobic here really wouldn't be worrying about feeling a bit sick if Ebola was running rampant across the Home Counties or there were militias staging raids just outside Bournemouth town centre.