It happens when towing a large load and include steep hills and mountain passes in the worst cases. What we are saying though in reality is that compared to an ICE vehicle EVs will lose more range relative to their maximum due to the small energy reserve they have. Of course an ICE vehicle will lose range but they have a much bigger energy supply on board even though it's used less efficiently. I'm hardly going to diss Tesla when I own one
TfL did some tests and struggled in the US because of the minimum speeds required on inter-states i.e. 70 mph and the distances between charging stations plus they towed the maximum weight. I did'nt personally like the way they did the test because really they could have tested a more and it would have been obvious that they would have struggled. However your dealing with the general public and people will buy an EV hitch a trailer with little or no preparation and expect it to work like their ICE truck for example. Plus of course they are a YT channel and they have to get views so if it just worked the video would be less controversial and more likely to attract dislikes from traditional ICE owners
Looking at some of the info for the upcoming utility style EVs coming out then 100-125 kwh packs will be very common if not the entry level.
TFL have done at least two trailer tests.
The Ike Gauntlet is the one you're talking about. That's a standard test they do with lots of vehicles, including almost every pickup in the last few years.
The other one they've done recently is the off road trailer trip. That, while not a standard test, is a standard trailer they use behind several vehicles. The aim there was to see how an EV pickup may handle a standard off road trailer.
I think a lot of the problem is Tesla enthusiasts only watch those episodes with the X and don't have any history with the channel, or understand what the channel is about. Too many of them are used to channels that start with "I have a BEV, how can I do this trip with it?", whereas TFL is more about "How does this compare to the next vehicle".
For the general public the latter is far more a realistic proposition as you say, but it riles up people that are potentially willing to make large sacrifices to be in a BEV.
Equally, its worth remembering that conversely to your last point, a lot of the Tesla youtube channels are there in part to spread their affiliate links. No need to annoy your fans that may use it and give you free stuff from Tesla.