The percentage wasn't the important part. Especially since people typically consider "half" to be a wide range, on top of the word "nearly" I'm also not sure where this less than 20% comes from.
Again, if you're going to diss someone, at least get basic elementary school division right. It's just frankly embarrassing. And again, far less than half the country actually supports him. I used a number of 40%. Half of 40% is 20%. Is 20% "almost half?" No, not even close. Even if I assumed that exactly 50% of every US citizen supported Annoying Orange, half of that, 25%, is still nowhere near enough to be considered "almost half."
And yes, it does build a narrative. The narrative that, I assume, is about not spreading 'scary' statistics about some group of people and instead focusing on proper policy. Except you know, you have to forget about all those times that Annoying Orange has been spreading 'scary' statistics about groups of people and then tacking on 'and some, i assume, are good people.'