To be saved one must hold to the essential doctrines of the faith like the doctrine of sin and the need for faith and repentance. A damnable false doctrine is to consider sin as something that doesn't produce a "negative effect" (as Mr. Haseltine calls it) and thus give people the false assurance that they can continue in their evil and suppression of the knowledge of God without the need for faith and repentance.
What a shame it is for so called "Christians" to enable an "institution" called "gay marriage" that promotes and flaunts the sin of sodomy and in fact aiding sinners in their pathway to hell. If I saw my friend who has a problem with drunkeness about to enter into a bar, I would not be his friend if I did not try warn and plead with him to not go in there. So if a person promotes an "institution" that will in fact confirm people in their sin and rebellion (i.e. Sodomy) then that person doesn't really love to see people set free from sin.
Charles Spurgeon said, "He who has no desire for sinners to be saved is not saved himself."
Silofulous, when someone claims the title of "Christian" the only ultimate authority for faith, morals etc. is the unchanging Word of the living God...not man's opinion or any kind of non-slippery slope argument. It therefore makes no sense to appeal to any other authority for "right" and "wrong"...otherwise someone could use a non-slippery slope argument as an excuse for any type of abomination known to God. Mr. Haseltine should instead be asking "What does the Word of God say about this." In Matthew 19 Jesus defines marriage as the union of male and female, thus "gay marriage" is not marriage according to Jesus' definition and is therefore sin in the eyes of The Lord.
So yes...to claim "Christian" in your designation and be pro "gay marriage" are mutually exclusive since true lovers of Jesus would never be pro-sin.
"I just don't see a negative effect to allowing gay marriage." That's because you, Mr. Haseltine, are your own ultimate authority. But then again, what must unbelievers turn to when they reject God's authority but their own selves....and then anything goes like rape and murder because everyone's left to their own preferences and opinions. ABSURDITY!
Very Christological Sermon! Nothing is better for the Christian's soul than to hear about a wonderful Savior! Sit back and let your soul be refreshed as it is nourished by the Bread of Life as preached by Steven Lawson.