>Yet, Tor pages I've read certainly weren't describing themselves as a tool of U.S. intelligence agencies funded by their fronts.

I'm not sure DARPA or Naval Research Laboratory are really intelligence agency fronts.

https://www.torproject.org/about/sponsors.html.en

Tor is supported by intelligence agencies because of the value it brings to them. For someone undercover, Tor is a great way to keep in touch, and if you're confronted you have a plausible explanation of wanting to buy LSD or watch kiddie porn or whatever most people use Tor for.