Freeway driving more difficult to drive speed limit than to speed?

Driving on freeway slower its more difficult than driving faster is it because the car is lighter or higher rpms give you more control or what i drive a fwd stock Honda thanks it's a lot easier to drive at 80 than 60

No. You're just not concentrating.

It really depends on the car and the way it is geared combined with the way the engine generates power/torque at different RPMs.
i had an old 2000 Chevy blazer which was geared for torque and the engine had a very low peak of torque and not much power after that. On that car, driving on the highway was easier the lower speed you went. Then I upgraded to a 2006 Hyundai Santa Fe. Even though it has s smaller engine will less power and less torque, it behaves better at 140 kph (86) than it does at 100 kph (62) because the way its geared means that the engine stays in an RPM where it makes good power. This let's me quickly accelerate to pass other should I need to.

as for your comment on RPMs for turning, that only really applies to track driving where you are pushing the tires to their limits in cornering. The idea is that when you are pushing the limit of traction, any additional forces added be it accelerating or braking will push the tires beyond their limit and they will start to slide. When tires slide they don't have nearly as much grip meaning you can't turn as hard. On roads, you don't push your tires in cornering as much but the idea is still present.

Nonsense. The higher the speed, the greater need for the driver to anticipate hazards further ahead and so the more demanding the task.