As always when these topics are brought up with that sense of urgency, I will raise my hand and ask "Whose ethics? Unethical according to who ?"
For example, right now I personally am considering a particular ML research project in cooperation with our local police agency. I am aware that in many places around the world there is an antagonistic relationship between the local communities or the people and their police system, where helping the police can be reasonably considered unethical or even outright evil in certain areas for totalitarian regimes. But I'm happy (or privileged?) to live in a place where I do trust my law enforcement to be on the side of our community, and I do consider helping our police to be more effective as not only ethically permissible but as a social good, as helping the people and country. With that being said, should I be worried about the research results being tainted and unpublishable? I can certainly imagine a perspective or validation rules that could label this as "line of research that shouldn't exist" simply because it does enhance the power of police that could also be misused against the community - but, as I said, at least for our community I consider improving police capabilities as ethically permissible and even desirable and see no need to import the "government is a threat to us" mentality from places which do have this (sad) problem.
Perhaps the example in the original article about an NSA booth at NeurIPS conference is relevant - like it or not, the voters generally have supported the concept that NSA should exist and should get funded, that their mission in general is ethically justified and necessary. While it has had specific projects and actions that are arguably unethical, it does not mean that it's reasonable to label everyone working for NSA as unethical and treat helping NSA as taboo - the society apparently considers NSA as a whole as net positive, and there is no serious push with widespread support to dismantle it and its functions. Similar arguments apply to military (is it ethical to be a soldier, to train to more effectively kill people at the service of your country?) and arms development. There's also the potential asymmetry of location - perhaps you might consider it ethical for a USA citizen to work for NSA and unethical for them to work for Russian or Chinese intelligence, and vice versa. Which ethics and whose ethics, indeed.