Human beings at an early stage were killed to produce these stem cells. This violates fundamental morality and decency. No, they never had a chance to become full-term babies or children or grownups, but they were alive, they were human, and they would have been babies if they had not been killed before they had the chance.
Another histrionic argument... an embryo is not "human life" that warrants protection. The fact that it can be frozen for 10 years proves it is not "life" but just a chemical glob of goo that has the potential for life.
The bill/law mentioned says nothing about the destruction of embryos except those that were going to be destroyed anyway.