Ahh. What is your first language? I'm learning Tagalog since I'm in the Manila area, but I'm not very good at it yet. :-(

Simply put, there is no objective morality if God doesn't exist. Things just "are," and any moral judgment you make is ultimately arbitrary. Love and morality are not meaningless because you are an atheist. They are meaningless if atheism is true (but it's not).

Homosexuality is a sin because it involves a twisting of God's created order. It is an abomination to God, and yes, it means that if you pursue homosexuality, you are a bad person. The good news of the Gospel is that God saves bad people. He gives them a new heart, and as a result, they repent and trust in the Lord Jesus for salvation from sin and from the wrath that they deserve. And all people deserve His wrath. All people need Jesus, who took the Father's wrath on behalf of His sheep so that they could be counted as innocent "in Him."

My citation of Romans 1:18-24 underscores the fact that you know God exists. Atheists cannot escape the fact that they are creatures living in God's created order, but they suppress their knowledge of Him.