If Jesus is the ideal would we say that he always behaved like a Christian? Would a true Christian curse a harmless fig tree for not bearing fruit out of season, causing it to wither? Would a true Christian place loyalty to himself above wife and child while declaring that he came with a sword? And would a true Christian condemn people to eternal torment simply over a difference of opinion?

Unfortunately their holy book endorses such circular reasoning, explicitly, in I John 2:19. Since the average literalist couldn't spot a logical fallacy at twenty paces, they just obey it.

As to morality: when I've been able to get fundamentalists to discuss the nature of morality, they generally are stuck on the notion that without god's authoritarian enforcement, all moral systems other than what they imagine god's to be are "just opinions" and neither objective nor enforceable. They can't / won't see that their own notions of morality are just their own subjective opinions and interpretations of (and selective ignoring of some parts of) scripture. They do the equivalent of plugging their ears and shouting "la la la I can't hear you" when you discuss what morality actually is and whence it comes.

Frankly I just haven't made any progress with them on this topic.

I name the fallacy, but I bet a lot of people think I'm a nerd for doing so.

Its all crap

I stopped trying to convince people that I'm moral and worthwhile without necessarily believing in their god(s)... Believers imagine themselves to be on higher moral ground because they waste an hour a week listening to fiction. Nothing will change their mind about that, no matter what you say to them...

Two monologues don't make up a dialogue.

I tell them that they’re moronic.

Walk away in total disgust.

You'd think the US Christian alt-right electing Trump would convince them otherwise.

Ask them to define what Christianity actually IS, what constitutes being a Christian in the most objective sense. Afterwards grill them on what groups of Christians are real Christians, and what their oh so holy texts say on the matter. If all these different sects all follow the core tenants laid forth by their religion, then they have no room to throw shitty Scotsman fallacies when one of their own steps out of line. Take responsibility for your groups actions and stop trying to discredit those who do wrong so to make your group seem like some pristine and faultless people.

Religions have to own up to their bad parts and do their best to keep those that blemish their name in check. You can't just automatically discredit the bad apples as not being true to the religion when they do something stupid or disgraceful. After all, they could have just been more devout than you.

Atheist don't commit as many crimes as Xians.