I am [a] European, and I am sure you, at least from a general and abstract point of view, understand that the USA are not the World, and that some of the things that seems so important to you, are just the construct of what the USA culture, politics, history etc ... but are just, to people from other backgrounds one of the many USA weirdness (as I am sure there are European weirdness, Swedish weirdness etc.).
IMVHO, YEC and the need to argue with them, is one of those.I actually didn't realize until I did some research prompted by the above correspondence that YEC is indeed a uniquely American phenomenon. I was under the impression that it was world-wide, and in fact there are a lot of non-American non-Christian creationists in general (most Muslims are OECs). But young earth creationism does appear to be uniquely American (and Christian). I didn't know that.
But all this is not about YEC per se. This is an exercise in trying to find common ground with someone with whom I vehemently disagree, and to see if I can learn some lessons from the experience that generalize to other domains. I ended up partnering with a YEC in part because that just happened to be the kind of person I could find who was willing to engage with me. I would have happily done this with a Muslim or a Mormon or a Jehovah's Witness (I've actually had a few conversations with Witnesses and found them to be quite knowledgable and intellectually honest. But it's a very small sample size.) but it turns out to be really hard to find people willing to engage in this sort of thing, and even fewer who are willing to be intellectually honest about it. (If you want to volunteer, please let me know!)
I happen to think that it's a good thing that I'm doing this with a YEC in part because the scientific evidence against YEC is so overwhelming. Figuring out how an intellectually honest person can sustain such a belief is, I think, interesting just in and of itself. It is not a simple matter of "cognitive dissonance" as Don Geddis has glibly claimed. Cognitive dissonance simply means "the state of having inconsistent thoughts, beliefs, or attitudes." In other words, CD is just a label for the phenomenon, it's not an explanation.
Whoever you are, American or European, religious or not, the world is full of people with whom you will vehemently disagree about something. Responding to that by retreating into enclaves of like-minded people is not going to produce good outcomes in the long run. This planet is only so big, and at some point you are almost certainly going to have to interact in some way with someone with whom you vehemently disagree. The world will be a better place if more people learn how to do it without resorting to violence. Even if you don't have to deal with Islamic State in your back yard, there could be other religious fundamentalists closer to home.
If you happen to be religious, you might want to follow this exercise (or even engage in it yourself) because it turns out that atheism is on the rise in the U.S. Atheists now outnumber evangelicals -- narrowly at the moment, but the trend is solidly in our favor. (If you're a social conservative, which is strongly correlated with being evangelical, things are looking particularly grim for you in the long run.) You might want to get to know us better, and in particular, find out why we "choose to reject God's grace", and why we nevertheless do not in fact rape and pillage despite having no apparent moral compass.
Finally, if you're a Christian but not a YEC (I'm looking at you, Publius) then you have a theological difference that you might want to try to resolve. At the very least, you differ in the interpretation of Genesis. Are you sure you understand YEC hermeneutics (never mind the science) well enough to definitively rule it out as a possibility? Because if you can't, then it's possible that you're making a mistake that will impact your prospects of salvation.