Home made mayo made from US eggs is not safe unless enough acidity is used and the mayo stands at room temperature long enough before consumption--because the pasturization does not kill salmonella inside the egg.
That said, I've made mayonnaise with unpasteurized US shell eggs literally thousands of times, tasting every time, and eaten it at restaurants hundreds of times. What anyone considers "safe" is relative. Fine dining restaurants across the globe sell millions of portions of it per day, as they do beef tartare, carpaccio, sashimi, French style buttercream and meringue, raw oysters, clams, flip cocktails, and zillions of other 'unsafe' things. US restaurants must sell tens of millions of runny-yolk eggs, and millions of Hamburgers not brought to 145 degrees internally.
They don't do so entirely without incident, but it's well within many people's risk tolerance threshold. Surveillance for outbreaks of serious strains (eg Salmonella Heidelberg, E. Coli OH157, etc) is pretty good— people usually seek medical treatment when the serious symptoms start, most GPs and emergency medicine practiciners are pretty good at knowing when they need to test, and epidemiologists do follow up before they even hit the requisite 3 cases to be considered an outbreak.
"*Pasteurized eggs have been heated to a high enough temperature for a long enough time to kill Salmonella."
Only 3 percent of the eggs sold in the US are pasturized though and if you make mayo with ordinary eggs, salmonella is a possibility.