Been through this before. It has to do with speed limits and trailer weight distribution.
So, you have to understand the correlation between trailer tongue weight, speed, and stability.
The rule of thumb in North America is to have 10% of your gross trailer weight as tongue weight. So, if you have a 3000lb trailer, your tongue weight will be 300lbs. A trailer with 10% tongue weight is very stable at speed, and its natural tendancy will be to not sway. If a gust of wind pushes the trailer around, it should quickly return to a neutral position. When you have a stable trailer with 10% tongue weight, speed doesn't really play a role in trailer stability. The trailer will be just as stable at 130km/h as it is at 80km/h. This is good, because North American highways are FAST. There are no separate speed limits in NA for vehicles pulling trailers. We often see trailers being towed at or above the speed limits, which in some states can be 80-90mph (130-145km/h).
Now, contrast this to Europe: The minimum tongue weight in Europe is 4%, with a goal of being between 5% & 7%. On a 3000lbs trailer, your tongue weight can be anywhere from 120lbs - 210lbs. BUT, a trailer with a lower tongue weight percentage will be less stable than a trailer with high tongue weight, especially at higher speeds. In fact, Europe has separate trailering speed limits that are lower than the normal speed limits. Trailers are limited to a maximum of 100kph on dual lane highways, and 80kph on single line highways.
Back to your Ford Escape/Kuga. In North America, your maximum tow rating is 3100lbs. With a 3000lbs trailer, you'll have a tongue weight of 300lbs.
In Europe, the Ford Kuga has a tow rating of 4100lbs. With a tongue weight of 7%, that translates to 287lbs. This tongue weight is pretty close to the maximum tongue weight that YOU are allowed to have on your North American Ford Escape.
300lbs of tongue weight is the maximum that the rear axle (and tires, suspension, etc.) can safely handle on a Ford Kuga/Escape. That 300lbs is placed 2-3 feet behind the axle, and acts as a giant moment on the rear axle. A 300lb tongue weight placed 3' behind the rear axle can translate to an extra 900lbs of load on that rear axle (with a commensurate lightning of the front axle). Weight distributing hitches can help alleviate this somewhat, but they can only do so much.
Engines and transmissions on modern vehicles are plenty strong enough to pull much higher trailer loads. The weak link is the rear axle and its assemblies (axle, springs, tires, etc.)