I think the answer to this question is that are afraid that juries might be more likely to pass the death penalty if they are aware that there is a potential benefit to other people from the death of the prisoner.
To complete the analogy, the concern is that using embryos for research might lead to the destruction of more embryos.
It doesn't. Embryos left over from IVF are destroyed anyway. The new guidelines allow using cell lines derived from leftover embryos. The Dickey-Wicker Amendment still prohibits federal funding for creating any new hESC line.
For those who think that embryos have a moral value, it is never right to use them as a means to an end. Using them (and destroying them), even for a good purpose, devalues them.
They should be equally concerned with IVF. Some are. Many aren't.
these reprogrammed adult cells seem to have all of the characteristics of embryonic stem cells
Many, not all. These techniques have advantages and disadvantages.
Finally, I have to point out that even though Obama claimed to eliminate the false choice between ethics and science, he still implemented some ethical rules - specifically a ban of reproductive cloning. I happen to agree with this, but I thought it was disingenuous of him to pretend to get rid of ethical barriers that restricted science. All he did was eliminate the barriers that he disagreed with and retain the barriers that he did agree with.
Obama called the Bush hESC rules specifically a "false choice". He never said he was going to ignore ethics.
I think that most American are completely unaware of the advances that I wrote about earlier - for the reprogramming of adult stem cells.
Most laymen who are aware of them seem to think they make perfect substitutes for embryonic stem cells. The ignorance probably balances out.