There's a podcast by two stand up comedians here in Estonia (well, WAS a podcast, now that Ari Matti is in the US and gathering international fame - no new episodes in months) where one of the very first episodes discussed this: Having a common enemy brings people together more than anything else they have in common.
"Oh we both went to the same school? Yeah, cool.."
"Wait, you ALSO hate that person? Of course you do, how could you not, they're terrible... Have you noticed how they speak? It's so weird..."
Euro SUVs can not be compared to American SUVs.
You go buy a hunking monster of a German SUV, a BMW X7 or a Mercedes GLS right now, they're actually shorter than the LWB versions of the 7 series or S-Klasse, at around 5.1-5.2 meters for the SUVs and 5.3 for the flagship luxury sedans (Maybach versions and such are longer ofc)
The SHORT version of the GM full-size SUV (Escalade/Yukon/Tahoe) is about that size. The full size version (Escalade ESV/Yukon XL/Suburban) is almost half a meter longer than that, at over 5.7 meters. Full-size pickup trucks get over 6 meters in length and those are completely normal commuter vehicles too. The Cybertruck isn't even a very big truck in the US.
Japanese, Korean and American manufacturers all have models that they consider normal for North America, but won't sell in Europe - though for the Koreans, those aren't even THAT big - the Telluride is only a bit bigger than an X5.
That's not to say that I disagree on the fact that we need to limit car size growth. But you can NOT compare Europe to the US. You drive around in more rural areas in the US on a single holiday trip and suddenly things like the Jeep Grand Cherokee start looking like small cars. The super popular "C-SUV" in your graph is a smaller vehicle than an Audi A4. A normal family car that can fit 2 proper child seats in the back and a stroller in the trunk in your graph is anything between C and D segment car or SUV. The average taxi, the Mercedes E-Class, is E segment.
Really the most stupid part to me is when people buy these C-SUVs. They don't generally fit more people or luggage than C-Cars, and because of the extra weight and height, handling and ride quality is more compromised. They also cost more than equivalently sized cars. Just get a C-Car or D-Car in the form of a wagon. E-Car if you really need space. Most of my cars have been executive sized wagons (5 series Touring, E-Class T-Modell, A6 Avant are all cars I've owned) and they'll beat a similarly priced compact SUV in pretty much any metric I can think of. I currently have about 200 kilowatts of power after a remap, do over 1000 km on a tank of diesel in mixed driving scenarios (1500+ on all highway), can sit in comfort all day long or race you on a curvy road, and carry half my furniture when I fold down the rear seats.