I am puzzled by the adjective 'sadomasochistic' as one will struggle to find any reference in the Bible where God could be described as a masochist, as well as a sadist. Florid prose such as this does give the sophomoric atheist a few memorable quotes to hurl around discussion forums, but it hardly inspires confidence that the book will be anything other than a relentlessly polemical screed.
Saying whether the Bible explicitly mentions a certain word or not is really irrelevant. The Bible (especially when translated to a different language from the original and read by someone with a different cultural understanding) is open to interpretation. This is why we have many different Christian denominations. Therefore saying that the Bible doesn't explicitly say something doesn't mean that it's not that way.
For example, some serial killers are sadomasochists, authors of books about such people may not have used that exact word to describe them but it is implicitly understood that someone who receives pleasure from inflicting pain on people and seeing others in pain is most probably a sadomasochist. It is what it is.
If someone told you to "Sacrifice your children on an altar in order to please me" then is it not probable that that person is either a sadist, a masochist or a sadomasochist? Regardless of the reasons for them asking you to do so.
Topic in hand (question being "Is God a Moral Monster"). Depending on your denomination, if you ignored the teachings of Jesus on morality (and the teachings that Jesus is God) and focus on other parts of the Bible there are lots of things suggesting that God is a moral monster such as passages in both the old and new testament which discriminate against virtually anything that is not a man. If it's true that Jesus is God then some times he is a sadomasochist and some times he is not.
I think the Bible in general (based on the number of stories about doing bad things versus the number which were about Jesus doing good deeds) teaches about being a "Moral Monster" where you should discriminate, that God is not always love, even leaving the rapture open to questioning.
In my opinion, morality, good, bad, love, hate, etc are all a matter of opinion. In the past (and even in some of today's religions), it was / is considered morally acceptable to beat your wife to the point of death if she refused to obey your commands. It was considered morally acceptable to rape women from another tribe and take them as your slave while you beat and kill their husband, just because she was from another tribe. The teachings of this have not changed, only people's understanding or interpretation of them, or their decency.
In summary, in my opinion of morality, and what I know from over two decades of reading the Bible, I do think that God is a Moral Monster.
Regards,
Ken