Absolutely, it is easy to say "they should remain celibate" when I'm not the one with the problem! It is always easier to say what others "should" be doing rather than looking at ourselves and where our shortcoming are. I can't imagine what it is like to be in the shoes of someone who is gay or lesbian and dealing with this. By the way, this issue is close to me, also. I have friends and family who are homosexual. In fact, my brother wrote a show that was off-broadway that deal with the whole Christianity vs. homosexuality issue.
In terms of God being unjust by creating people with a sin so powerful, they must deny their own sexuality. I disagree. Although man is born in sin, the sacrifice of Jesus Christ on the cross made it possible for us to overcome our sins. So, His gift to us is the ability to live a righteous life, but only if we depend on Him for strength. Often, people get hung up on the "fairness" issue. However, if my desires are for money and I never have it, do I have a right to cry "unfair"? How about someone born with a brain damage or someone else who suffers from major depression or schizophrenia. Honestly, I do not believe life is necessarily fair, so I don't get hung up on the concept of fairness.
Now, you asked, "Isn't it easier to assume that the verses dealing with homosexuality are just the prejudice of those times and that God calls us to something better in THIS time period?" Yes, it is easier to deal with the verses that way. Many times I have wanted to. I would love to say it's "okay" and dismiss it. However, I do not believe I can do that and be intellectually and spiritually honest with myself.
Let me say this about your friend. I'm saddened that he has rejected Christianity. I do not believe that one has to be heterosexual to be a Christian. I believe that God will accept all of us, in our sinful conditions, and love us, if we turn to Him. I believe that it is a daily struggle with sin (believe me, no one wins every struggle!). I do not believe someone struggling with homosexual desires is any more sinful or worse than me. In fact, I am a lowly sinner who's only hope is the grace of God.
My belief is that each person has to decide for themselves what path they will take. I believe the appropriate choice is celibacy. However, it is not my decision to make for them. If someone disagrees with me (and they are truly seeking the truth with a clear conscience), then I do not judge them, but pray that we both may be enlightened with the truth. If I am wrong, I pray for God's forgiveness and for His guidance in helping me to find the truth. If they are wrong, I pray that God will show them and forgive them. I believe in freedom of conscience. I believe that each individual answers to God, not me, for their behavior. I answer to God, not them, for mine.