The only way I could see speed as the only witnessed "factor" in that accident would be more of an aerodynamics, hitch setup, tow vehicle to trailer weight issue, etc. This assumes no human error but more an unrecoverable sway/wobble/loss of control.
My point is that towing my 7000 lb TT with my 4500 lb Tahoe would get me sucked in and pushed out when I pass a semi when only 3mph faster than the big rig.
After upgrading to a 7500 lb F350 dually, I could pass a 65 mph semi at 85 mph with one hand on the wheel and total stability.
Higher speed could exacerbate the situation, but it's not the root cause, just a contributing factor.