heh,
other than the fact that we were designed to move and yes apply work-through-space to get by in this world, exercise can be doubly beneficial for modern health. To put it simply, is really about shaking those atoms around not to mention allowing tissue to die and rebuild and breath. some people do this just with some light yoga or rebounding or tai chi etc.. so while single effort workouts like running might not be the best options, there are other ways than lifting to engage a full spectrum of bodily movement
I guess in some ways, other than laziness there are some ideologies present that might guide one not to be very active specifically related to raw. I think some folks like Aajonus recomend that people do not exercise starting out and perhaps for good reason because a.) it uses energy that might be better used for healing and b.) the very reason its benefical which is it stirs up alot of crap in the body which people may be sensative to.
The other claim which seems pretty absurd is that one can maintain a fit trim body without exercise. I'm skeptical of this one myself, but as long as one can 'bring it' when necessary (Aajonus himself claims to kill it on boat rowing or hiking without any problems in energy or endurance) it really wouldn't be required to be active daily or do any kind of weekly training. I'm sure once tribes became more established in hierarchies, some individuals were not as active as others and still maintained strength and virility.
since online ordering and butcheries didn't exist back then, i wonder how many of these people feel that they would have obtained their meat in the wild by sitting on their asses?
so to me I see what you are saying is bothersome only when people talk about like how much they should eat based on their desires or instinct or whatever, when they arn't even capable of bringing down the very animal they are eating, and their energy expenditure largely reflecting what type of diet and foods they choose to eat. But if someone says to me they order meat online and arn't very active that doesn't bother me generally, whether its very 'paleo' I do not know.
I've said this before but there is probably a basic level of fitness (being able to move heavy boxes up flights of stairs, doing basic squatting and lifting motions etc...) that is indicative of health because these things will effect your heart rate and the way your body uptakes oxygen, not to mention all the other things you can find online linking exercise to sleep/mood etc...
Its likely without this basic fitness it is either an indicator of poor general health, OR something that can be changed with proper exercise to possibly make all the other aspects of health (nutrition/breathing/sleep etc...) run alot smoother.