I understand your points completely, I often feel that the God of the OT seems incompatible with Jesus Christ.
But a historical and cultural context clears things up a lot. How could a loving God command the destruction of all those innocent people? The argument sounds good, but it is utterly false. The unstated assumption is that the people who God ordered destroyed were morally equivalent to the Jews, who replaced them. However, this is what the Bible says about the people who were destroyed:
"It is not for your righteousness or for the uprightness of your heart that you are going to possess their land, but it is because of the wickedness of these nations that the LORD your God is driving them out before you, in order to confirm the oath which the LORD swore to your fathers, to Abraham, Isaac and Jacob. (Deuteronomy 9:5)
These people, the ancient tribes, had pretty awful practices, including burning their own children to death as a sacrafice to gods:
"You shall not behave thus toward the LORD your God, for every abominable act which the LORD hates they have done for their gods; for they even burn their sons and daughters in the fire to their gods. (Deuteronomy 12:31)
God is both loving and righteous. Those that say He is righteous to a fault should also contemplate then that he is loving to a fault. He, according to the NT, offers the forgiveness off our sins in return of faith in him.
The cultural context dictates that these tribes were unruly and had some awful practices. They would most certainly not have had open minds to Gods plan.
I agree that the OT "version" of God can seem too harsh at times. However, throughout the OT, God is said to be “merciful and gracious, slow to anger and abundant in loving-kindness and truth” (Exodus 34:6; Numbers 14:18; Deuteronomy 4:31; Nehemiah 9:17; Psalm 86:5; Psalm 86:15; Psalm 108:4; Psalm 145:8; Joel 2:13). He is slow to anger, we are told. It seems that the pagan tribes pushed this patience to the limits. Their survival might well have been detrimental to the survival and growth of Judaism and Christianity. Perhaps in the OT cases, the ends did justify the means as:
-Gods actions showed sinfulness in not tolerated
-Gods actions showed he was real, and powerful
-Gods actions paved the way for the birth of Judaism and Christianity
My friends and family showed concern and saw this church as a bit of a cult, but I continued to get more involved with the church. Before I knew it, my book shelf was the proud home of books explaining away all my doubts: intelligent design apologetics, daily devotionals, books sold to me through a brochure the church would distribute every month or so. I remember debating God with my friends and using the same sort of straw man arguments you can still see being used online today. "Evidence of God? The whole universe is all the evidence I need!"
I went on my J1 in 2009 and that was when I realized what I had gotten myself into. The church I was a member of models itself around the large evangelical churches of America, and visiting those churches made me realize the fakeness of it all. It all seemed to be about money and was anti-intellectual. There was no room for debate and no room for moderation. It was all black and white, heaven and hell, saved and unsaved. I guess that is what attracted me to Christianity, the absolute nature of it. I realized my church at home was much the same, just on a smaller scale. There was always a notion floating around my mind that it was BS though, that I was falling for something I shouldn't be. It began to grow that summer.
I can still remember reading the Bible and having so many doubts, trying to justify moral wrongs within it and massive contradictions. Eventually I realized I had to cop on and get out of the faith before I was in too deep. I was always proud to be a critical thinker who questioned things but was slowly starting to just accept things the Bible/preachers said at face value. I was struggling massively with my sexuality. I had told me pastor about being gay and how I did not think I could "fix" it, and he had encouraged me to seek help of Christian counsellors. That same week at church service, he acknowledged people in his congregation "were struggling with the illness of homosexuality." A man who was close to the pastor came over during worship and, speaking in tongues, put his hand on my head and prayed over me. I later found out he was praying for me to be "healed".
The final nail in the coffin was when I started losing friends. I had become judgemental towards them and scoffed at their "lifestyle". I had a devout Catholic friend who I would often engage in debate about how the Catholic Church got scripture wrong, hoping I could help him become "saved." As once close friends started to find me hard to be around I realized deep down that I was being an idiot, basically. I realized I had put my mind in a place that was based on superstition, on nonsense, and that I was losing important and real things because of that: critical thinking, relationships, my own dignity.
I'm glad to say I am religion-free for around 4 years now. I got out of the "Biblically based reality" and am so glad I did so. I worked hard to regain the friends I had shunned and to become comfortable with myself in a real way. I felt free enough to think for myself again and to question things. I researched evolution and topics like humanist ethics without feeling like I was looking at something morally wrong, and I have never looked back.
Today, I am a baby-eating atheist. How times change.