I have 2000 jeep tj, that's the one with coil springs instead of leaf springs, and you can barely keep it on the road by itself never mind trying to tow with it.
The trailer looked to be in surprisingly good condition after that. My guess is they had too much stuff loaded in the back end. The tongue appeared quite light. I agree though, I would not want to tow with a Jeep either.
Not sure you can blame the tow for that situation. Its hard to say from that video as to how it ended up like that - heading in the wrong direction. could have been many many reasons for it - including being cut off and hitting the highway seperator and spinning around.