If you're seriously surprised, you need to read more labels.
If you aren't seriously surprised, heck, read more labels anyhow.
I found out I had Celiac disease (wheat/gluten allergy) a couple years back and I've read a lot more labels since then (companies are actually getting better about not sticking flour in random things but you still have to watch out), and of all the surprises that resulted, the sheer prevalence of HFCS was by far the biggest. It's not just sweets... it's everything.
It's very uncommon in anything labeled organic. In the US, organic foods can't be genetically modified, and nearly all the corn used to make HFCS is genetically modified. So HFCS tends to be avoided in favor of evaporated cane juice. Tasty!
Hey, why is there corn in my ketchup?!