take on the gay letter

saw the letter of the father disowning his gay-son which has made the interwebs this week and really find that it's becoming more depressing to read the papers every day..   I'm still kind of confused where in the Bible/Torah/Koran it says that we should hate and outcast people but I'm admittedly not a biblical scholar 

"James: This is a difficult but necessary letter to write. I hope your telephone call was not to receive my blessing for the degrading of your lifestyle. I have fond memories of our times together, but that is all in the past. Don't expect any further conversations With me. No communications at all. I will not come to visit, nor do I want you in my house. You've made your choice though Wrong it may be. God did not intend for this unnatural lifestyle. If you choose not to attend my funeral, my friends and family will understand. Have a good birthday and good life. No present exchanges will be accepted. Goodbye, Dad."

I get that there are different generations but what I don't understand bigotry especially when it comes to disowning your own kids but I guess people have disowned one another for similar things in that past..  Then again this is a culture which will gorge themselves on chicken to show how much they love Jesus/hate gays and who will damn gay people to hell for ruining the sanctity of marriage while going through their third divorce for infidelity.   

Although I did read the following commentary which I thought was appropriate on how he should respond

Dear Dad,

Since gay is a choice and I wasn't born with it I can only conclude that you and the environment you raised me in have resulted in my being gay. Thanks a lot for ruining my life and damning my eternal soul to hell.

Your Son