+1
I will add that murder, disbelief and zina are all held at equal level in the koran. Does the koran directly order the death of apostates as well? No it does not. It is the hadith that orders the death of apostates.
Even if the Quran does not say it, the authenticated hadith say so:
Sahih Bukhari 4:260
The Prophet said, 'If a Muslim discards his religion, kill him.'
The only reason the Quran did not say it is because at the time the emphasis was on spreading the belief, not retaining it.
In any case the Quran is filled with vitriolic verses against non-believers and people guilty of crimes against Islamic morality.
All in all it creates a culture of retribution & violence that spills into honour killings & mindless violence.