Some of that statement is true, but that is because of the fact at the factory the units are installed with a throttle stop to prevent them from exceeding 25 MPH. Most of this is done to get the young riders used to the new products and some of this is for liability reasons and for CARB and emission reasons. But there is hope.
I have clocked my unit at over 48 MPH! All you need to do is adjust the throttle stop. I am including some pics to help those who are confused about this.
The first thing you need to do is inspect the unit for proper adjustment as it sits now. First, and of course for safety reasons, turn off the unit. Since we are going to be playing with the throttle, I don't want the unit to take off and run over anyone and for someone to get hurt!
Now, remove the center engine cover or depending on the model, gain access to the throttle body on the engine. You will need to do this to verify the current throttle adjustment. Second, depress the throttle peddle all the way down to see how far the throttle body opens up now. Once the gas peddle is all the way down, see if you can turn the throttle body 'butterfly' valve any more open. This is the large round object that the throttle cable is connected to that looks like the carburetor. If you can still turn the round butterfly then you either need to adjust the throttle cable, or remove the throttle stop. Now, lets look at the gas peddle and see if the throttle stop is still installed. In the pic below, you can see item #33. this is the throttle stop. You can simply remove this item, then the throttle peddle or gas peddle will have its full leverage, allowing the throttle to open all the way. You will need to move the large round rubber grommet to the position as shown in the photo. This will allow the throttle peddle to move through its entire range. Next is the throttle cable adjustment.
With the throttle peddle left alone, there should be some play in the cable, you DO NOT want the cable to be so tight that it is applying the throttle when no one is pressing on the peddle. You need to adjust the cable so that there is enough slack that allows the throttle to completely close when the throttle peddle is released, but also when the peddle is all the way down, the throttle butterfly is all the way open. With the peddle all the way down, you should pretty much not be able to open the throttle butterfly up anymore. A very little is considered okay. If it is too tight, it will only put tension on the cable and want to break the cable early, so be careful. The first pic shows the throttle body butterfly with a throttle cable adjustment. the second pic shows the rear of the throttle peddle cable adjustment area. The third pic shows the throttle stop and how it looks