I think you'd probably do better to license the software individually to users that meet your standards. Sell it for cheap or even free if you like. if someone is so unethical as to participate in these industries or activities you dislike; why would you trust them to honor your license restrictions?
Could be more manageable:
* Implementing a broad clause that reserves me the right to decline clients.
* Setting standard pricing for the general market.
* Offering discounted licenses to entities that I choose/like.
This tiered approach might be easier even though I was hopping for another route. It lacks of transparency compared to a public clause.
Thank you for contributing to the discussion.
Many companies offer discounted or free licenses to organizations as a form of support. Very vanilla, well understood.
The legal right to say "I cannot serve you as a customer because of moral / ethical conflicts" is being argued still in the USA but seems to still be fairly well understood.