I'll agree with you that Catholics should understand that the two creation stories in Genesis fall into mythos/allegory instead of literal fact, but as I mentioned before, it's hard to determine what the appropriate venue would be.
I don't think that is the problem. I think the problem is that the many Catholics truly believe that the Church has no position on the scientific view and that it is up to the individual person to choose whether it is literally true or not. A stronger emphasis on the fact that the creation myth is a parable just like the ones Jesus told and that it isn't literally true could be dropped into sermons pretty easily.
I'm not saying that the priest has to teach the science. Simply that he has to make clear that Genesis is a simplification.
That probably would be the best way to do it, but even then, the impact would be somewhat limited. That passage from Genesis would probably come up only once a year in the normal cycle of readings, at least for Sunday Mass; in fact, I'm not sure if it's read outside of the Easter Vigil service. A priest could choose to focus his homily for that week on that particular aspect, but it wouldn't have a place on a weekly basis. It would definitely be better than nothing, though.
People who happened to attend Catholic school, and specifically Catholic high school, are really the only group whom I'd assume is most like to have been taught the concept in no uncertain terms.
Have they? I was under the impression that the Catholic Church leaves it up to the individual to decide. You do have plenty of Catholics who are firm YEC believers. Are you saying that the Catholic Church considers them to be wrong?
There is a huge difference between teaching evolution in science classes in school and teaching its place in the creation myth during religious instruction. Which one is being done?
I'm honestly not sure how the Church specifically views Catholics who believe in YEC in terms of being "right" or "wrong." As you've said, the Church's general position on evolutionary theory is one of having no problems with it as an explanation for the Earth's natural processes. I don't know that they would ever actively condemn YEC proponents as acting against Church teaching, though, as it wouldn't necessarily be within the purview of faith.
As for the school question, at least in the high school I attended, we were required to have four years' worth of theology class. I'm fairly certain that, in the year we covered the Old Testament, we studied the creation story in the context of allegory or myth, emphasizing that it wasn't meant as a literal scientific account. Coupled with the normal study of evolutionary theory in biology class, I think it paints a unified picture of evolution as being the factual explanation. But as I said, this would only really apply to people who had attended Catholic high school.
I will not deny that individual Church officials have made some profoundly stupid, and sometimes outright harmful, science-related statements in the past, and I'm not about to defend them. But the general attitude of the Church today toward scientific research is relatively benevolent, even if there are logistical difficulties in ensuring that every practicing Catholic out there understands this. That's really the only point I was trying to make, nothing more.
Similarly I will agree that out of the major branches of Christianity the Catholic Church is undoubtedly the least hostile towards science. I'll agree that they are almost completely neutral towards it by and large (unlike others who are downright hostile). But I will point out that while it leaves it up to people to decide whether to take the bible literally or not, it can hardly be said to have embraced science.
I'm not really sure how much active "embracing" any particular religious faith can truly accomplish, though. In the broadest sense, science and religion exist to answer different questions, or at least different aspects of the same questions. I don't think any particular denomination of Christianity could, or even should, become something like an active cheerleader for science as a whole, as it wouldn't fit into the role that religion plays in people's lives. Stating something like, "Scientific research is a way to understand the universe that God created," and leaving it at that, is probably in the best interest of all concerned, as it acknowledges the importance of science without intruding on it.
I think there's a substantial difference in stating, "Several Church officials have made troubling statements about science," and instead saying, "The Church as a whole has a troubled relationship with science." That's where your point was getting lost on me.
As I pointed out above the Catholic Church is mostly neutral towards science. Wouldn't you say that any relationship where the two parties were largely ambivalent with occasional spats was a troubled one? 
Only if you're trying to share the same bed.
