My understanding is that it's both -- the egg laying hen population in the US has some amount of salmonella infection, plus washing the cuticle off does something to promote salmonella growth in the egg (contamination from the feces on the shell able to get into the egg?). I don't have citations for this, though, and would be curious to learn more, if anyone has a good authoritative source.
USDA statistics from 1996 on salmonella in eggs put it at 1:10,000 to 1:20,000 chance of an egg being infected. It's a case of odds, and how you cook the eggs. If you're taking a dozen eggs and making mayo from scratch, then making 100 sandwiches in a cafeteria, the odds are sufficiently high that once a year you're going to make everyone sick. If you're making sunny-side up eggs, the yolk won't get heated enough to pasteurize it, but the impact is at least greatly reduced. If you're properly scrambling the eggs, then yes, they get hot enough to reduce the pathogen count to be a non-issue.
USDA statistics from 1996 on salmonella in eggs put it at 1:10,000 to 1:20,000 chance of an egg being infected. It's a case of odds, and how you cook the eggs. If you're taking a dozen eggs and making mayo from scratch, then making 100 sandwiches in a cafeteria, the odds are sufficiently high that once a year you're going to make everyone sick. If you're making sunny-side up eggs, the yolk won't get heated enough to pasteurize it, but the impact is at least greatly reduced. If you're properly scrambling the eggs, then yes, they get hot enough to reduce the pathogen count to be a non-issue.