Christians often also make huge leaps from what the Bible says to how they interpret it [or simply ignore it when it suites them]
You yourself find the bible self-contradictory if taken literally. It's a principal of hermeneutics to interpret various passages in a way which makes them consistent. Both internally and externally.
You can't change the words of the bible from what they say and mean to something that they do not say or mean. If the words state that God is responsible for evil, that is the meaning.
