Your points are valid, but I think that building AI has benefits beyond simply enabling people to use that AI. It advances the state of the art and makes even more powerful AI possible. Still, it would be good to know about the amortized cost per query of building the AI in addition to the cost of running it.
I don’t see why this argument works better against AI than it does against microwaves. Those are used hundreds of millions of times a day too.
With regard to sugar: when I started counting calories I discovered that the actual amounts of calories in certain foods were not what I intuitively assumed. Some foods turned out to be much less unhealthy than I thought. For example, I can eat almost three pints of ice cream a day and not gain weight (as long as I don’t eat anything else). So sometimes instead of eating a normal dinner, I want to eat a whole pint of ice cream and I can do so guilt-free.
Likewise, I use both AI and a microwave, my energy use from AI in a day is apparently less than the energy I use to reheat a cup of tea, so the conclusion that I can use AI however much I want to without significantly affecting my environmental impact is the correct one.
I’m not saying that ice cream is healthier than a normal dinner, just that if I really crave something sweet then the cost to my health of eating it periodically is actually quite low, whereas the cost of some other desserts (baked sweets are often the worst offenders) is relatively high. That means that a lot can be gained simply by replacing one dessert with a different, equally tasty dessert. Hence my ice cream advocacy.