I am not suggesting that zero-carb is automatically a disaster for everyone. What concerns me, though, is this:- most Arctic tribes do eat berries in summer, even if they eat practically 99-100% meats, raw or cooked, at other times. They , presumably, also eat the fermented stomach-contents(ie plant-matter) of the animal-carcasses they cut up. So, 100% carnivorous diet for life, for humans, may be  rarer than expected.

That's very true
look at the coyotes - they are carnivorous, they do like carrion, but they also eat some fruits and vegetables

  Are you suggesting I should be worried for my long-term health?

maybe it is good for you to do zero-carb for some period of time, so that you'll heal from your abdominal problems
but cutting all carbs and eating only "meat and fat" for the rest of your life wouldn't be good - that's certainly not paleo
albeit for now this zero-carb could be the only option

I really don't get any benefit from the raw vegetable fat in avocado.

the same is with me
I haven't eaten it for several months. But in the winter when I ate them almost every day I realized that I became hungry quite rapidly after eating them. The same is with egg yolks.
animal fats like suet and marrow are simply the best!

Zero-carb approach could not be enough
the real problem in modern world is dental toxicity - toxic fillings (e.g. amalgams), root canals, cavitations, etc.
read "It's All in Your Head: Link Between Mercury Amalgams and Illness" of Hal Huggins
when you've got mercury in you body (in your teeth) you'll always have overgrowth of Candida albicans, as it is transforming very dangerous form of mercury into some less dangerous, so it plays quite postive role (only in this case, of course)
you should fight the real cause and with zero-carb rawpaleodiet you'll certainly win