note that many parts of the US enthusiastically adopted stem cell technology (https://www.cirm.ca.gov/about-cirm/history) but unfortunately federal-level policies set by conservative leaders have ameliorated the ambitious plans of that project.
The opposition was/is entirely to the death of embryos in order to obtain some stem cells for research. It's not as if it's some anti-science policy.
It's simply a continuation of anti-abortion politics, which a lot of people feel very strongly about and invokes a ton of ethical questions. As long as there can be a perception that someone was killed in order to provide the stem cells to save someone else, that's not going to go away.
Find ways to research stem cells without doing that and all of those concerns vanish.
"All the embryos used in CIRM-funded research were donated from IVF clinics. They had either been rejected for implantation and were going to be destroyed, or the couple had decided to stop storing the embryos for future use. The embryos used to create embryonic stem cell lines were already destined to be destroyed."