They are fundamentally different types of vehicles. But putting that aside, if you want to compare the largest payload that each vehicle can transport you wouldn’t just use the pickup truck’s GVWR, you would also include it’s towing capacity. There’s a reason 90% of the time people use a pickup to haul something, they’re towing.
I’m not sure I fully understood, but it sounds like you have several concerns with their competition? And those concerns are around asking people to design things that are potentially unsafe, giving bad advice for selecting materials, and awarding prize money to submissions by Prusa employees?