When we use Math.random(), it will generate some random number between 0 and 1.
Suppose when you run your program first time, it may generate 0.3, which is less than 0.5. So
var judgemental = true
!judgemental = false
While using && operator if one of the condition becomes false, then the whole condition results as false. So the list
<li>Nacho Cheez Straight Out The Jar</li>
does not get rendered along with other list items.
If you run your code again and again Math.random() will generate different numbers , if the number is > 0.5, value of var judgemental becomes false. If number is < 0.5, value of var judgemental becomes true.
Hope this helps.