... this is certainly not what I had in mind.

I assumed it was, based on the "not in moderation".

But the Mormon church also forbids a glass or two of wine with dinner, once a week.

Yes it does. You are free to read section 89 where it is so forbidden to see why.

In any case, one can look at the rings of trees, match them up to older trees, match those up to still older trees..

Not sure the trees would have died. Also not sure of the exact nature of the flood. The myth is an extremely common one and myths are usually based on some sort of fact. That we haven't definitively shown what this was based on does not mean that it did not exist.

it is unethical to eat animals, for example, which the church would find to be incorrect

I just showed that the church would not find this to be incorrect. I actually know some members that hold this exact position and they are members in good standing. Like I said some of the presidents of the church have held this position.

Something being culturally being less acceptable has nothing to do with whether it is incorrect or not. That the culture within much of the church would be biased against holding a vegetarian or vegan position it is true but that is nowhere near the same as saying the church itself holds the position to be wrong.

This is EXACTLY what I mean by "playing logic games"

I assume that you do not hold that position then. I have had multiple discussions with people that did hold that position and it is one of the more annoying things to deal with.

I'm not even sure which one is responsible for more deaths per year,

Alcohol causes about 23,000 fatalities a year. Pools appear to cause about 3,500 fatalities per year. Tobacco causes about 400,000 fatalities per year. Cars cause about 40,000 fatalities per year.

Many of the alcohol deaths are also car fatalities as well.

Per usage alcohol has a higher death rate then either tobacco or pools. Over the long term tobacco clearly has a higher death rate. I am unsure as to if marijuana has a similar long term usage effect. To be consistent society should either make alcohol and tobacco illegal or legalize all other substances with a similar amount of harm. I personally think each state should be able to make the decision.