Reform-style teaching, a.k.a. Discovery Teaching, means that students are supposed to discover all of mathematics on their own.
This makes a very nice straw man to hold up for ridicule, but it is almost completely false. Teaching based on constructivist theory requires providing a structure within which students can construct their understanding. Autonomous learning is an important aspect of constructivist teaching, but such autonomy is a far cry from the kind of aimless wandering often depicted.