You can have a test that says, "Write the letter A." If you can write the letter A, that's easy to measure in a standardized way. Unless different schools teach different styles of writing...then how do you decide which style is correct? Maybe some schools think it matters, other schools don't.
Yes, there are basic skills that need to be mastered, and testing is important. But I think using the term "standardized testing" is just ridiculous.