Especialy High Fructose Corn Syrup (HFCS) is a very "out there" worry for some people it seems. And also incorrectly. The key, as always, is moderation and looking at the real world.
A good read is this Science-base Medicine article. The best quote you can probably get out of it is the ending sentence:
And stop worrying that HFCS is poisoning you and your children.
The point is made in the intro that we are not just looking at fructose/HFCS. It starts with this supporting claim (referenced)
Despite the fact that some of the underlying mechanisms are not clear, the evidence seems pretty solid that there are real risks to high fructose consumption.
But don't stop there, because here is the kicker:
However, the question remains — is HFCS more of a health risk than other sweeteners?
There is a lot of information in the article, and I suggest you read it to completely understand the sugar problem, instead of the "quick-win" frights that are raised on typical places.
One of the things mentioned is this: (emph. mine)
HFCS allowed food manufacturers to use less sugar — and thus fewer sugar calories — in their products without compromising sweetness.
So it is probably not the healthiest -as is all sugar- in high concentration, but although there is truth in the problems with fructose, it is hardly a big problem compared to your intake. WOrry about other things, like a balanced diet.