Some people is just dense I guess...
When you have changed the handling and maneuverability of your vehicle for the worse, it's best to use extra caution. For example, my XJ on 33s with 5.5" of lift and no sway bars doesn't do 80 on the freeway anymore. Does it have the power and gearing to reach it? Yes, is it wise? No. My 73 Ford with the slide in camper in the bed could pull 70-80 mph probably, but it wouldn't be wise, so I stick to around 60.
Just because your truck has the power to reach high speeds while towing doesn't mean that it's safe at those speeds. Next time you've got your trailer hitched up, try and perform an emergency lane change at highway speeds. Practice on a deserted road though so nobody else gets caught up when your truck goes careening out of control.