They didn't defend well either(they had bad technology). For example, a British Empire army of 58,000 was able to defeat an italian army of 500,000 in Libya
Strategically, you're right. But tactically it was a different story. Notwithstanding the almost complete destruction of the Italian 10th Army during the early part of the North African campaign, the Italians would prove to be one tough cookie, as the Allies landing in Sicily would soon discover. Same with their artillery units---some of them would keep firing their obsolete guns at the enemy until they were literally overrun.
And yeah, their technology did suck; I once heard that a bullet from a pistol would punch through the armor of an WWII Italian tank. Not sure if it's true, but I wouldn't be surprised if it was. And even then, they had a bright spot: motorized vehicles. Italian motor vehicles were actually of better than average quality. Hell, Montgomery himself used some of them!