I'm just going to correct the things said that particularly bother me:
The above claim isn't quite true. For example, the Gauls in ancient France were well known to routinely fight stark naked in battles.
That's an example of humans standing the cold for a
short period of time. They fought for a few hours max naked, then came back to their clothes, fire and houses/shelters. Unless, of course, they were still pumped-up from Panoramix' magic potion
Then there is the issue of all those immigrants from the 3rd world looking for a better life, but, interestingly, always seeking out colder climates when possible.
I think it's safe to suggest that colder climates is not what these people are looking for, when coming to the -wealthy- northern regions of the world, such as Europe and USA.
What weakens his argument re the Ethiopian highlands is that clothes are not really suited to the generally warm African climate. But clothes are admittedly more likely to have been used for much colder climates outside Africa.
Africa, just like any other continents on this planet, minus perhaps the two poles, is home to various type of climates: desert, steppe, savanna, tropical rain-forest, mediterranean...all not equally warm, or dry, or moist...
Wikipedia on Ethiopia's not-so-warm climate:
"The predominant climate type is tropical monsoon, with wide topographic-induced variation. The Ethiopian Highlands cover most of the country and have a climate which is generally considerably cooler than other regions at similar proximity to the Equator.(...)The average annual temperature in Addis Ababa is 16 °C (60.8 °F), with daily maximum temperatures averaging 20–25 °C (68.0–77.0 °F) throughout the year, and overnight lows averaging 5–10 °C (41.0–50.0 °F). Most major cities and tourist sites in Ethiopia lie at a similar elevation to Addis Ababa and have a comparable climate."
Not to state the colder temperatures in the more elevated parts of the country.
In such conditions wearing clothes might've been a necessity.
I think that in the end no faulty historical science, no uncertain arguments and no personal convictions (I'm also including myself when I say this) can truly decide what is one individual's optimal living place. It is everyone's responsibility to find the place where they can live the best with the least need to rely on "unnatural", accessory means. There is obviously more than one Garden of Eden on this Earth. The key is to experiment, see if you can manage every aspect of a certain environment, be it the climate, the terrain, the edibles, their level of access depending on the season....
If you can manage all those aspects in the colder regions -Not only the climate-, it's all very fine. If not, it's all right, back out a bit in more comfortable environments and let time eventually decide when it may be right to move forth, if it ever is.
Personally I am more attracted to the idea of going back to warmer regions, but if I do this it would be in a very progressive way, like for instance moving to a more southern European country such as Spain, gradually adjusting to an already less familiar environment. But that's just my own suggestion to myself.
It's every person's task to find their own optimal habitat, be it Siberia, India, East Africa or New Zealand, and to live more in tune with it.