It's all part of His "bizarre and unknowable plan". But how about this? At one point in history, the Israelites were hanging onto survival by a thread, with enemies all around. At that point, with warfare largely limited to human muscle, victory was largely dependent on how many spearmen, slingers, shieldbearers, etc. one could field. Victory often meant survival, with the losing tribe or people being scattered if not obliterated. In such an environment, homosexuality threatens the group's survival, as it needs all the children it can sire and raise. (Even in the High Middle Ages, child survival was hit and miss, usually with no better than even odds of survival to adulthood even with all the advantages money and power could secure.) Homosexuality in that environment would be selfishness. Later on, the Israelites were more numerous and more spread out, even if not necessarily free. The individual could be allowed more freedom without endangering the rest of the group. Think of crossing the road; as a small child, approaching a road will bring swift punishment because it endangers the child. But as the child matures, such rules are relaxed. In fact, have to be relaxed, else the child cannot mature.
First of all, I want to point out that there is ambiguity in the Bible as to whether the New Testament abolishes the laws and decrees of the Old Testament. For example, Matthew 5:17-19:
"17 Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them.
18 For truly I tell you, until heaven and earth disappear, not the smallest letter, not the least stroke of a pen, will by any means disappear from the Law until everything is accomplished.
19 Therefore anyone who sets aside one of the least of these commands
and teaches others accordingly will be called least in the kingdom of heaven, but whoever practices and teaches these commands will be called great in the kingdom of heaven."
Given that there are conflicting passages in relation to this, I think the interpretation suggesting that Old Testament laws were abolished is illogical,
at least in regards to any issue for which the New Testament is silent. So, for example, Leviticus says death for homosexuals. But the New Testament is silent on the punishment, if any, for homosexual behavior. Romans condemns it as an "abomination" but says nothing one way or the other about punishment. Did God really intend his followers to suddenly have no laws whatsoever on many issues? Doesn't seem all that likely.
As to your explanation, it's very creative. I'll give you that. However, allow me to suggest a rather pedestrian, alternative explanation for why we see a God with a totally different personality in the New Testament than the one we see in the Old Testament. These books were written by many different people, the New in an entirely different era than the Old. The personality of God, and the laws and decrees of each, reflect the differing beliefs, opinions and value systems of the people who wrote these books.
That, or this perfect being is rather fickle, and not just in regard to homosexuality, but in regards to many things.
Sometimes the simplest and most mundane explanations turn out to be the correct ones.
