I am not a marketing professional but I think that any notion of ethics in Marketing is inevitably very strongly linked to the product or service that one is trying to bring to the market. For example I don't see much possibility of cigar marketing (in terms of efforts to expand its marketability) being ethical.
The more a product or service is aligned with the common notions of ethics, the more ethical its marketing will be. So I think that luxury products marketing will necessarily be less ethical than poverty fight or sustainable development products or services marketing, such as education, health and green technologies.
So I think maybe marketing and ethics can go together, depending on what you are bringing to the market.
Thank you for your explanation with examples in very simple language. If I understand your point, there is no "black and white" answer to the question I posted. The answer is perhaps, as you explained, "it depends....."
The best way to respond to such questions is to explain them what marketing really is (i.e. creating, communicating, and delivering value in exchange of value). Give a few examples of successful social awareness campaigns in your country. Then tell them that "it depends" on the value of the cause/product/service is on offer for the consumer.