This is a technicality, and a weak position from which to ridicule.
Why is this 'ridicule'? This happens to be the General Religious Debates section. This is the place where opposing ideas are supposed to meet, and disagreeing with seemingly flawed dogma doesn't strike me as 'ridicule.
If God is omnipotent and created everything, then He must be responsible for evil--that doesn't strike me as 'ridicule' nor does it strike me as a weak argument. It seems to be quite sound in its challenge to popular Christian-Judeo teaching, even if it is not perfectly indefensible.
There are likely good answers and defenses to this proposition, but what are they? If God can do anything, why could he not create a world in which all his creations have freewill yet do not suffer from the evil of others?
Why did God allow Satan to use his cunning against mankind's innocence? If we look at Garden of Eden story literally, then Adam and Eve didn't even know what a 'lie' was when Satan deceived them. How could they possibly defend themselves against Satan? Didn't God set them up to fail? And even if He didn't, isn't He still responsible for evil if He created a world in which it could actively operate?