They memorized PEMDAS and assume that M comes before D, such that $30 \div 6 * 5 = 1$, when the intent was for $30 \div 6$, then $5*5$.
Here's another: " $10^2 - 5^2 \div 5$.
The order of operations is most appropriately a way to ensure that everyone can communicate in a consistent fashion, that there isn't really a "natural reason" as much as there was a human one. "It's just an arbitrary rule" was one of the most-viewed posts on MathCurmudgeon, relating the story of an expression that only 30% of over 300,000 Facebook users got right. (And because Facebook is what it is, they were all certain that they were correct.)
$6-1*0+2 \div 2$
... but here is an interesting viewpoint. What is your take on it?