Your vehicle and roof must have a minimum driving (dynamic) weight capacity of of 165 lbs/ 75 kg. For tents weighing more than 165 lbs/ 75kg, the maximum weight capacity of the rack and vehicle must be greater than the tent weight.
Thule's recommended roof rack weight capacities can be found in the printed Thule Fit Guide and on Thule's website.
For other brand roof rack applications, check the vehicle and roof rack owner's manual for maximum weight capacity.
The weight capacity of the tent in use (static weight) can exceed the driving weight capacity of the rack/vehicle because the loads are dispersed throughout the tent and partially supported by the ladder. As a guideline, the static roof rack capacity is approximately three times the dynamic weight capacity (roof rack and tent included)
I would suspect that Hyundai's weight limit is not based on the structural strength of the roof rails but on the handling impact to the car. If you put a lot of weight on the roof and suddenly have to swerve while driving at highway speeds, the car will be much less stable, and the risk of rolling the car much higher. So if a different brand roof rack allows a greater weight on the roof, I would not recommend that you take advantage of it.