For me, a python user since the late '90s, the answer has always been simple:
Guido has taste.
Guido has taste.
At least we don't have to use it.
Why was there a backlash for this operator? (looks kinda neat). Was it breaking things?
I have a long list of grievances with Python, but the walrus situation would never crack my top ten. Put effort into removing cruft from the standard library, make typing better, have the PSF take a stance on packaging. Anything else feels a better use of time.
Whatever, it won. I will never use it, but when I see it will have to scratch my head and lookup the syntax rules.
You may be interested in https://learning-python.com/python-changes-2014-plus.html for a sense of what some old-timers' aesthetic sense is like. (I agree with many of these complaints and disagree with many others.)
Maybe he did some kind of deep, programming design. It just sounded in that account more like he threw together whatever solved his problem with some nice ideas baked in. Again, that's if it was true that he invented it to automate tedium during BLACKER VPN.
BLACKER is described here: https://ieeexplore.ieee.org/document/213253
For public examples of A1, look up SCOMP, GEMSOS, and VAX Security Kernel (VMM). Those papers describe the assurance activities required for A1 certification. At the time, due to bootstrapping requirement, tools like Configuration Management didn't have to be A1. People used all kinds of stuff, like Wall building Perl.