It should be noted that more often than not there are strong reasons besides ignorance and incompetence for a project to arrive at a certain state.

https://en.m.wikipedia.org/wiki/Wikipedia:Chesterton%27s_fen...

It shoud be stressed that a developer should not assume all his predecessors were wrong just because he doesn't understand why some stuff ended up being the way it is. The world is packed with developers who proud themselves of fixing things that were never broken, and in the process break stuff.