Look to your left. Look to your right.
Both of those people are working for a foreign government.
At least one of them does not know it.
Trust no one.
Both of those people are working for a foreign government.
At least one of them does not know it.
Trust no one.
The generous argument is that it's only fair to the student that they should know quickly whether they'll be able to get through the material. Failing fast can be merciful.
The truth is probably more complicated. Let's just say that the student population ended up looking a lot like the TA and professor population. Lather, rinse, repeat.