Good explanation.
As @directive0 said, the diodes (triangles in the above circuit) only conduct in one direction.
On the AC wave (top left) in the positive half, two diodes are conducting. In the negative half, the other two diodes are conducting.
The two sets of diodes are connected so that the positive half and the negative half of the sine wave come out on the same line. Since the waveform on the right of the image is all positive (ignore the bumps), it is considered DC.
You tease