Sure it feels better not being a collaborator of your own demise though.
Seriously, this attitude sounds like keeping the knives under lock at your home in case your wife decides to murder you. If you think it's a possibility, then I guess this poses harder questions than where to keep the knives.
I'm going to assume that you're debating in good faith and will accept a powerful but unsympathetic example. The Golden State Killer was caught because his family members used commercial genetic tests, allowing investigators to triangulate him through DNA left at the scene, despite him never linking his DNA to his identity: https://en.wikipedia.org/wiki/Joseph_James_DeAngelo#Arrest,_...
Obviously this was a terrible man, and I certainly don't regret him being in jail. However, it demonstrates that your relatives can expose you to privacy violations without your knowledge or consent, and likely without their knowledge. It's like when an app asks for the list of your phone contacts, it's not just your privacy you're surrendering.
If we ignore that the man in particular was a horrific serial killer, which I know is hard to do, this shows how people can suffer consequences from other people taking these DNA tests, and surely you can see how that kind of sucks? Like, this shows the technical possibility, which is unaffected by the actual reason for doing so.
But your example is that of a licit, even desirable use of those dna tests. They can be used for bad purposes, but that is what you have a government for: to decide what can be done and what can't. Health insurances obtaining your dna sequence from a third party to change your premium? Abso-fucking-lutely unacceptable. (And besides, at that point, what keeps the insurance company from asking your dna directly, unless you want to pay max price?). If you can't keep the government from allowing such things, you should either campaign to change the government or emigrate. This whole "let's keep a profile as low as possible because the government might go against me someday" is both a bit paranoid and fatalistic. If you distrust the government so much then you should put all your energies in changing it, not in keeping a low profile.
The only power you as an individual truly have is to lower your risk profile if such an adverse event were to happen. History has shown time and time again that governments can change dramatically for the worse in short timespans, and if they have data to use against you then they will definitely use it
When the literal Nazis took over Belgium and the Netherlands, the actions taken by the resistance in each included attempting to destroy official records of who all the Jewish people were: https://en.wikipedia.org/wiki/1943_Amsterdam_civil_registry_... and https://en.wikipedia.org/wiki/Jewish_resistance_in_German-oc...
Much harder to do that these days, when backups are cheap.
And I'm frustrated because I haven't trusted my government or these companies to be responsible with that data even before it was glaringly obvious they wouldn't. So now here we are in the "I told you so" phase, and it just sucks how much of this data is already out there, ripe for misuse. And now it's just too late.
> Or when the government decides to start rounding people up based on ancestry
And you think that not having sent your dna to 23andme would be a good protection from that? Like, since you are among the smart ones who didn't send the dna, you can keep quietly minding your business while the government "rounds up" people on a racial basis?