You're spending a lot of effort and well made points arguing against a person who isn't trying to see where you're coming from. Their take is pure libertarianism where a concept of freedom outclasses any real consequences. Like most of these pure-freedom arguments the whole thing pivots on a carefully contorted definition of "harm" - your clear examples of harm being discussed apparently don't count and there isn't a good faith conversation about why, they are just being hand waved away.
I think your attention is better spent on other commenters.
I'm not sure what I can do to recognize and steelman this position. There is no way to justify telling someone far away that they aren't allowed to capture photons which have bounced off of your skin that doesn't amount to a position of maximum egotism.
A person's existence does not entitle them to control and authority over every particle that interacts with them.
I'm allowed to see you. If you are in a place where I can see (ie, in public), then I can see you without even telling you I can see you. If I can see you - regardless of whether the technology I use is the result of biological evolution or electronic innovation - and you never even realize you've been seen, then by definition I have not harmed you with that act.
So, let's identify the _actual_ acts of harm. Trying to limit what CBP is allowed to see - when we can't even verify what they've seen - is not a path to relief from their tyranny.
I don't think that's hand-wavy. I think it's consistent. And unafraid to speak truth to power.
If you think you can summarize what I'm missing, I'd love to hear it.
I think your attention is better spent on other commenters.