The US congressional research service thinks EU subsidies are more spread out among all types of crops, including fruits and vegetables, whereas US policy focuses more on grains, sugars, dairy, and oil seeds:

Okay, but the data I just showed showed that Americans eat similar amounts to European countries of those things. A lit bit on the lower end of oils, definitely on the lower end of grain consumption, on the higher end of non-tuber, non-grain fruit and vegetable consumption, and a little bit on the lower end of dairy consumption. (And some European countries eat much more dairy)

That’s not a direct subsidy of food processing of course, but the crops the US chooses to support ends up incentivizing it.

Yes, but Americans eat less of those crops and more fruits, vegetables, and meat.

Cultural factors are a thing but I think they’re used far too often to explain away trends at the population level and the effects of public policy.

I agree, another big part is that Americans are able to afford it, a lot of fast food chains for example have been billed as a bit of a more luxury choice internationally as compared to the US, just because the prices are similar to US prices but wages are much lower. Basically labor costs are lower in the agricultural centers of the EU- and manufacturing machinery costs are higher.