I'm English and personally I don't have distaste for American people, or think they're diabetic golems addicted to preservatives and shitty television. I also think the food superiority thing is a bit of a cope from Europeans trying to cling onto something they can still be "best" at. They did this to us a century ago when we were the global superpower as well.
I will say though, I do think European geography helps out a lot with us getting better, fresher and local stuff at standard chain supermarkets. Distance is a huge factor, to me. I honestly think most Europeans and Americans struggle to comprehend the difference in size between the two places. To put it in perspective, we import lots of our fruit that requires warmer weather from Northern Africa. The distance between Morocco and Britain is about 2200 miles, but the distance between California and New York is just over 2900 miles. In other words, I can import my grapes from not just another country but another continent and it will still take less distance to travel than it would for a New Yorker to have grapes grown in California, the same country.
What might be 'locally grown' for an American might be comparatively local as something made on the other side of the country for us. In addition, I'm no expert on US agricultural policies state by state but I imagine there's much less emphasis on individual states being somewhat self-sustainable in terms of meat, dairy and crops than there is in each European country. I can go into any random UK supermarket and find a majority of the fresh produce that doesn't require too much sunlight was farmed at a place I could drive to in under 10 hours. Hell, with the channel tunnel, even if it was made somewhere else in mainland Europe, I could still get there in the same time-frame. I doubt I can walk into a random US supermarket and find the same amount of food was made within the same proximity.
But, the thing is, Americans don't need to have their chain supermarkets carry local produce because they all have cars which can drive them to hipster boutique grocery stores, farmers markets or to the farmer themselves. Sure, they pay a lot more for it but the average American is so much wealthier than the average European that the extra price is utterly meaningless.
Also, for any Americans who've stuck around to read this, not sure if you can get it but try Wensleydale cheese, it's great shit.