The difference between morality and ethics is commonly used as such:
morality: Distinction between right and wrong on a specific, or individual level
ethics: a system of moral principles. Usually invoked/developed by systems.
When you claim that
“We are being controlled by externalities”
then that is due to the ethics invoked by these externalities which try to impact your individual moral compass.
The christian church usually claims that morality is absolute, since it comes from god. If this was true and you consider that “there’s no salvation outside the church”, this makes the church the arbiter of ethics and by extension: morality. At least in their logical framework. Therefore, it is only natural for the church to talk about morality, when it actually is talking about their ethics.