No Christian of the real kind would ever so allege, that "God had given (them) homosexuality." That very statement reveals a person to not know Christ.
I pray for all homosexuals, including Sullivan. I pray for anyone who claims the Light to be darkness and the darkness to be light, and most homosexuals do that, in my experience.
I do not accept any one's random presentation that they are Catholic. We as Christians are asked to "test the spirits" and to evaluate who is who and what is what based upon how Christ instructs us to do so.
About homosexuality, if a person continues to declare themself as affiliated with homosexuality -- in effect, to be a "homosexualagendist" by doing so -- they are defying and denouncing what God commands. If a person recognizes a sin, even if they confess the sin and seek forgiveness, but do not repent of the sin, they are not bearing the "fruit" or presence of a renewed person in Christ. Because, true repentence based upon the strength and presence of Christ "casts out" the sin, there is repentence, forgiveness is sought, and the "new man" exists and the sin is no longer not attractive but usually is repugnant if there is true repentance.
A person continuing to declare both Christian and homosexual is engaging in abuse of the first and promotion of the second. As key example here, Andrew Sullivan not only does not denouce homosexuality but he promotes it and shares his enthusiasm and support for and about it; he may remember what some Catholics were like or who he thinks Catholics are culturally, but as to his own state of person, he is identifying himself as not a Catholic -- to the contrary, he identifies with and continues the sin, while denouncing repentance for the sin.
Those who continue to declare homosexuality do likewise and they choce the sin over Christ. Christianity and relationship with Christ and with His Church is not subject to cultural memes and cultural, socio-acceptabilities that vary based upon what is acceptable and admirable on a human level, but upon absolute principles and relationship with both Christ and His Church.
Matthew 7 ( 21-29 ) - these are the words of Jesus Christ:
15 "Beware of false prophets, who come to you in sheep's clothing, but underneath are ravenous wolves.
16 By their fruits you will know them. Do people pick grapes from thornbushes, or figs from thistles?
17 Just so, every good tree bears good fruit, and a rotten tree bears bad fruit.
18 A good tree cannot bear bad fruit, nor can a rotten tree bear good fruit.
19 Every tree that does not bear good fruit will be cut down and thrown into the fire.
20 So by their fruits you will know them.
21 "Not everyone who says to me, 'Lord, Lord,' will enter the kingdom of heaven, but only the one who does the will of my Father in heaven.
22 Many will say to me on that day, 'Lord, Lord, did we not prophesy in your name? Did we not drive out demons in your name? Did we not do mighty deeds in your name?'
23 Then I will declare to them solemnly, 'I never knew you. Depart from me, you evildoers.'
24 "Everyone who listens to these words of mine and acts on them will be like a wise man who built his house on rock.
25 The rain fell, the floods came, and the winds blew and buffeted the house. But it did not collapse; it had been set solidly on rock.
26 And everyone who listens to these words of mine but does not act on them will be like a fool who built his house on sand.
27 The rain fell, the floods came, and the winds blew and buffeted the house. And it collapsed and was completely ruined."
28 When Jesus finished these words, the crowds were astonished at his teaching,
29 for he taught them as one having authority, and not as their scribes.
You need to calm down.