I think I was misreading the wiki. Acidic = low pH, yes? That's what they meant, anyway.
That article mentions the original Hellmann family, who were German. That's the only commercial brand I know, too, that comes close to being real mayo. I think a lot of people buy the odd things that Kraft invented as mayo substitutes, like Miracle Whip, and who knows what's in that.
When I can be bothered to haul out the food processor, I do sometimes make my own -- so easy to do through that drip tube. But then it's not going to keep for long, and there's all that mess and fuss, whereas I just want a jar I can dip into occasionally sitting there in the fridge. So Hellmann's still has me sold.