Interestingly, this article [0], indicates that in theory at least, it may be possible to develop a privacy-respecting secure network that is capable of optionally (per node operator) rejecting some traffic. However, assuming such a thing is possible, it would still not satisfy the TLA’s (assuming what they’re really after is the ubiquitous transparency).

[0] https://news.ycombinator.com/item?id=21169768