God "created" sin? I don't think so. Yeah, don't you know, it was God's conspiracy... (sarcasm)
These people are simply over-imaginative, and turning Homosexuality into a sin-less behavior just requires that.
What God did create was free will. Satan used his free will to sin. Those who damn God for creating sin don't know much about God. God could have obliterated sin from the moment it occurred, and then all would follow God out of fear. The time will come. Those who blaspheme God will doubtless know when it does.