OK, I will bite. The crappy defensive game came from not having a midfield or attack of note. That simplifies things.
And as a matter of fact, we did not have much of a defense either... Truly a disastrous European Championship for us (not that we ever do well in our European competitions).
Now let us stop discussing football. Or we will slide into the 'Italians play crappy defensive football' diatribe. For the record, I do not agree - we won the last WC with quite a high number of goals. If that is defensive football, so be it.