Yeah, that was what I found as well. Butyric acid in sufficient qualities smells pretty much like vomit. Apparently (based on reading Reddit threads) Americans are used to the distinct smell.
Slighty off topic, whenever there's a discussion about food (especially cheese/beer/chocolate/bread), Americans tend to get defensive and say "well, if you go out of your way to buy PROPER cheese/beer/chocolate/bread, it's actually fine". I understand it must be tiresome when Europeans (and snobbish Americans) shit on anything American, but I never understood this logic.
The issue - from what I hear, I haven't lived in the US, so I don't know the food quality - is that in most European countries, you can buy store-brand beer, or cheap cheese, or bread from the bakery section of a supermarket, and have a satisfying experience with what you buy. The fact that people make the argument "well, you have to buy high-quality stuff" in the first place suggests that the cheap stuff is no good in the US?
I tend to shop at what is probably close to the Polish grocery equivalent of Walmart, I'm careful not to overspend - and I don't eat completely crappy food unless I specifically go for it.
I get why some food and drinks in Europe can be seen as having an over-inflated reputation. Like, I'm no wine connoisseur, but I think French wine is WAY overrated. I prefer stuff from, like, Hungary, and my wife always goes for South American wines. But the fact remains that you can get like a 5€ bottle of wine in Paris, and it's more likely than not to be pretty good (and stuff in Paris is *expensive*, so it makes 5€ seem even cheaper). I feel similarly about food in Europe in general, from my limited experience. In Poland in particular, you can eat for dirt cheap without much trouble and much searching - especially with stuff that's part of Polish culinary tradition (like sausages and whatnot).
[/rant]
But again, I haven't been to the US, so I fully accept that the horribleness of common American food might be hugely overexaggerated. I'll admit that whatever I ate that I've been told is "regular" American food - especially chocolate-based stuff - was less than impressive.