The above quote was probably not said by Otto von Bismark, althouth it's often attributed to him.
Nonetheless, the analogy is generally accurate. In making sausage, one uses the ugliest, most unedible, parts of an animal. The message is, sometimes you can take nasty, worthless, raw materials, and with the right mix, spice and curing, come up with something quite tasty.
The same can be said for law. Sometimes you can watch people childishly propose idiotic legislation, and after much mixing, knashing of teeth and negotiating, it can result in something worthwhile.
On the other hand, sometimes the end product is just rotten sausage.