Even if you believe that homosexuality is a sin (it isn't), you still cannot treat them worse than you would anyone else.

The heart of your message rings true. Jesus tells his followers to love one another, as He has loved us. That is to say that we should love each other unconditionally.

According to the Bible, it is worth noting that homosexuality is a sin. It starts out in the Old Testament, which is filled with some of the most clear cut examples here:

Leviticus 18:22:
22 Do not lie with a man as one lies with a woman; that is detestable.

Leviticus 20:13
13 If a man lies with a man as one lies with a woman, both of them have done what is detestable. They must be put to death; their blood will be on their own heads.

So it was pretty clear what happened to homosexuals in pre-Jesus times. Then Jesus comes along and tells us to love one another as God has loved us, and to let one who is without sin cast the first stone. Our treatment of homosexuals should be better than it is, but the actual teachings haven't changed much since the pre-Jesus times.

1 Corinthians 6:9-11
9 Do you not know that the wicked will not inherit the kingdom of God? Do not be deceived: Neither the sexually immoral nor idolaters nor adulterers nor male prostitutes nor homosexual offenders 10 nor thieves nor the greedy nor drunkards nor slanderers nor swindlers will inherit the kingdom of God. 11 And that is what some of you were. But you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and by the Spirit of our God.

(Personally I find it interesting that it specifically states male prostitutes, leaving it ambiguous regarding female prostitutes, but I digress.)

Romans 1:26-28
26 Because of this, God gave them over to shameful lusts. Even their women exchanged natural relations for unnatural ones. 27 In the same way the men also abandoned natural relations with women and were inflamed with lust for one another. Men committed indecent acts with other men, and received in themselves the due penalty for their perversion. 28 Furthermore, since they did not think it worthwhile to retain the knowledge of God, he gave them over to a depraved mind, to do what ought not to be done.

So the Bible is pretty clear about this issue, from front to back, before and after Jesus, pretty much anyway you want to look at it. Now, going back to the original point, it is true that Christians shouldn't treat these people any worse because of that. However it is a clear mistake to presume that homosexuality isn't a sin by the Bible.