He's talking about a dual carriageway (so, the Exeter example in your post above works), why would you not just be using cruise control? I drive up that particular hill often and never need to think about it. The car just goes up, at the speed set on the cruise control, as it has done in every car I've owned since 2004.
The ability to easily go up a hill on a dual carriageway when using cruise control isn't a benefit of an electric car, its a benefit of any car with an engine that has more than about 100 horsepower. It was, however, presented like no petrol or diesel car would do it.
Have you not noticed how many cars you fly by when you go up Halden Hill? I went up last Friday morning and passed 30+ cars, in fact by the top the speed differential is often a bit much if you are maintaining the speed limit.
There has to be many reasons for this, a combination of:
1. Not using cruise
2. Cars underpowered or driver reluctant to change gear (manual)
3. People don't like revving the nuts off their cars and just have mechanical sympathy and accept slowing down is kinder to their car.
4. Scared senseless
EV's don't need any gear change, they don't need you flooring it, and even with cruise on, every EV has more than enough torque at the right end of the speed range to not slow down..
We have two pool cars (Focus 1.0T Auto, Civic 2.0 eCVT) that can't make it up the A417(It's a single carraigeway, two lanes going up the hill 60 mph fast road) without slowing down by 5-10mph even with cruise control on, and one of those will disable cruise as well when it figures out it can't maintain it.. They may struggle with Halden Hill too.. Yet the VW eUP rattles up there at the speed limit no problems, as does an i3, and an ID.3 will accelerate heavily up there..
My argument would be that in general EVs make it easier for more people to not lose speed in their normal driving style. On top of that, even with cruise they have less fluctuation because they can modulate the torque from 0-100% without a gear change so it's all instantaneous, going up the A417 has even higher powered torquey ICE cars fluctuating by 2-3 mph and not being the most consistent.
And yes, of course a 530d / m340i auto with cruise on will blast up just fine.. I've been driving up Halden Hill for 35 years, I'd be lucky if 1 or 2 others going up are maintaining their speed, the rest all start slowing considerably by the top.. In fact it's something that sticks out to this day.. cars have got faster, yet the number of cars slowing never seems to change..
because I flit between ICE/EV all the time, I notice the different characteristics, so even though I use cruise/autopilot type features as much as possible, I still occasionally drive 'manually' and then it's quite obvious how much less throttle input you need..