Liberal Abrahamic belief without an inerrant old text can be held by moral be- lievers. OT objections aren't all equal. http://en.wikipedia.org/wiki/Ethics_in_the_Bible#Ethics_in_the_Hebrew_Bible http://en.wikipedia.org/wiki/Argument_from_morality
Certain aspects, like famines, would be matters of God's prerogative, not human morality, of a God presiding over all the cosmos just as life isn't held to human morality. Yet someone can believe in life for the good of life and add afterlife as a sweetener. Interpersonal ethics are a different concern and followers would have more prerogative if obeying a God proven to them. I know no proof of God but an ancient intervention could be a modern faith choice.
If it's assumed the flood didn't happen the question of God's morality is like questioning the morality of someone playing GTA: I have the prerogative to run over old ladies to beat the timer in a race yet nobody is actually harmed. You just enjoy or find meaning in the story.
The best stance for criticizing the God of the OT would be in regard to something like killing gay people as abnormal which seems wrong even if followers had proof of God or herem if they didn't. Then again modern believers typically don't consider themselves as under Mosaic law, consider those who claimed to be as only brought along so far by God, may consider herem as an exaggeration of actual old tribal disputes, criticize conservative stances, etc.