You need this to be about religion, because you are playing a game with multiple religions. But, murder of unborn humans is no more a religious issue than murder of any other subset of society not based on age, say, murder of humans based on race. If murder based on race (instead of age, or physical location, or state of dependency) were legal in the United States, rest assured, the religious pro-life movement would be fighting to ban raced based murder. Would you oppose them because they are trying to impose their religious views on others? But, the fact that they oppose it doesn't mean it is solely a religious issue. It would be wrong by secular standards, too. The same secular reasons for banning one also apply to the other.
If you think age killing is fundamentally different than race killing, please explain why? I think both are wrong morally for religious reasons, and both should be illegal for secular societal reasons.