The reason is simple if you love them you want them in God kingdom and to get that we must obey God, I repeat we are commanded to love all humans but abhor sin as sin is evil because it damages the soul we must abhor the evil of sin. The two main commandment are to love God above all thing and our fellowman as we love ourself. If we see the lost and dont do everything to turn them to God we dont love them nor do we love God.
The process that the Church must indicate is, homosexuals must repent for their sins (this is the same for all sins) in order to get back to God and get the help that they need to withstand the temptations that lead then to this unnatural behaviour sanctioned by God, sin is evil because it separates us from God and His assistance in developing virtues one of them is self-control.
God does not demand that they change and become straight what He demand is that they control this unnatural behaviour. The loving kind God that I know is the one that desires that all be saved and gave us the manual (the Bible) to guide us to Him and conform us for a living in His kingdom.
1Cr 6:9 Do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived. Neither fornicators, nor idolaters, nor adulterers, nor homosexuals, nor sodomites,
As a Christian I believe that the epistles are God inspired and the constitution of the Christian Church, I am sad that you think of God as evil, but what can we do it is your opinion and your message.