Fair enough, but I'm still not gonna argue with the historians who's job it is to know this stuff. 

I'm not saying to argue with the historians, unless you actually have evidence in which case go for it, but your confidence should be proportionate to theirs.  I've seen debates between mythicists and those who advocate for a historical Jesus, and I'd describe the confidence  confidence level of historical proponents as "pretty sure".  So, I'd say that is the appropriate level of confidence that anyone without specific expertise should have.    

How can we derive guidance from something that we don't understand? And why take guidance from someone whose motivation we don't know? Why worship something we don't understand? Why even trust it?

Buckle up.

1). His existence is not really debated.  His divinity, however, is.

2). Living, suffering and dying for what you believe in doesn't make what you believe in true. Mohammad was real, suffered and died for his cause I bet you don't subscribe to the Islamic faith, do you?  John Smith? 

3). Prophesizing a Messiah doesn't mean anything. Nothing specified Jesus.  Only vague allusions to a king, a messiah, etc...

4). Claiming a prophecy as being fulfilled is itself a self-fulfilling prophecy. If today I said there will one day be a great leader born out of England, well that's a pretty easy prophecy to claim as fulfilled if one day a great leader is born out of England of which surely there will be. 

5). But indeed it does.  Simply on the grounds that you cannot prove it is not. And a fairy tale (or fictional story, fable, whatever you like to call it) is merely a story of intentional creation or of unverifiable reality. To say nothing of the replication of stories of creation, sin, flooding, plagues, virgin births, resurrections, etc...since the dawn of time.  They were merely that - tales, stories, fables, etc.....until people learned to use them as a means of control.

6). Correlation is not causation. And happiness polls such as that fail to grasp the broader factors that lead to happiness.  Society, social support, community, finances, etc...   If you live in a highly religious location, family is highly religious, etc...it's easy to understand that happiness would be tied to being part of that highly religious community.  Not from the religion itself but the simply nature of humanity and wanting to belong to something that supports you.

7). Lol.  Have you seen the divorce rates among everyone? Nearly 50% of all US marriages end in divorce or separation. Further, your claim about long-lasting might actually be a bad thing.  Many Christians see divorce as wrong regardless of the need.

8). See number 6 again.

9). What the hell is a Christian diet lifestyle?  Oh, what.  You mean don't eat animals originally offered as sacrifice by pagan religions.  Don't eat things that slither.  Don't each shellfish (you're missing out) or fish without scales (again, you're missing out). That diet?  Because it actually doesn't say anything about limited red meat. Not just that, but other parts of the Bible completely say otherwise...eat whatever.

10). A. An increase sex drive does not have a thing to do with romantic love. Rather silly to think you must reduce your sex drive to have romantic love.  B. How do they know read meat increases sex drive?  Science.  It's called a study.  Take 100 people.  Have half eat red meat the other half eat no red meat.  Compare their reported sex drives post dinner.  C. It should also be noted that red meat was often considered a status food eaten only by those with sufficient means. 

11). I wish. Do you realize how different the world would be if they actually 'did what Jesus would do'? Most Christians are what I call garage Christians.  They think going to church makes them Christian.  But this is not more valid than standing in your garage makes you a car.

12). Uh, no.  Under slavery, colonization, war, exploitation, land theft, etc...was the west built.

13). No. Again, happiness is a broad set of factors that have far more to do with community and social circumstances than religion.  Why do you think the Nordic countries continually rate highest on these polls? Certainly isn't their religion given that church attendance and affiliation has dropped significantly over the past 4 decades.

14). I can make up a fairy tale that is 99.99% true....still a fairy tale.

15). In truth, it wouldn't be.  But it becomes important when it is used to establish law, institutions, policy, social acceptance, education, etc.... 

16). Nobody is saying Jesus is fake because we can explain rain.  What we are saying is that what we used to attribute as the actions of Gods (and demons) has a long his of becoming far less supernatural after extensive study. Further, when you cannot answer a question and you then give a supernatural explanation, you tend to stop trying to answer the question altogether. Think of all the knowledge lost if we never questioned anything we couldn't initially explain?

17). That's precisely why they are marked as fake (or at best extreme embellishments of the truth - that fish I caught was this big...). Water to wine?  When you understand chemistry and physics, you recognize the irrationality of this 'miracle'. 

18). There is nothing convenient about it. It's chemistry and physics. If you want to play the God card, you can say it's God's own rules that are being broken by miracles.  So how is that a convenience for atheists?

19). This goes back to Point 15). In general, it doesn't matter unless it impedes on matters it shouldn't.

20). Why can't we understand the Big Bang and where quarks and photons come from? We've come an incredibly long way in our understanding in just the past 100 years.

21). Room for God is irrelevant to scientific development. You can have room for God and study the cosmos in earnest so long as you don't rest upon the God of the Gaps fallacy. Again, it's mental entrapment of limiting yourself and your studies because you'd rather just say God did it than actually explore the facts.

22). Well, you already know this fallacy.  Who/What created the creator.  A watch may never understand the watchmaker...but the watchmaker was still created.

Because it theorically means good for all of us. 

I've often thought not to do a full breakdown of posts like these, and while you are correct that it often serves little purpose in persuading the individual being quoted, it does have value to the community at large.

I may not persuade him (though it would be great if it did and it has on occasion) but it might persuade someone else on the periphery. Another member, a lurker or a guest. 

And of course, there is the community factor itself.  For some, it's entertainment.  For others, it stokes newer debate.  So in that sense, I may not be doing a full breakdown for the sole benefit of whom I quoted but rather for the benefit everyone else.

"Good" based on what?  From who's perspective of morality?