This kind of logic only works if the percentages for each industry are all equally that small, so you can treat them as all equally bad, but they are absolutely not.
The single biggest non divisible sector you can realistically come up with is "personal transportation", but even that is only 10% of global co2. You can look at other sectors like "industry" and "energy" and I can guarantee you will be able to easily split things down into sub categories which have <5% impact on global co2 emissions.
But they didn't split it up like that. They said all data center emissions irrespective of what those data centers are used for — which can be an extremely wide variety of things since data centers basically run our entire network information internet economy. That's much more like saying all transportation emissions instead of splitting it up by type of transportation. Yes, that doesn't include the full life cycle emissions of creating the data centers. But I'm pretty sure that transportation, as a proportion of emissions, doesn't also include the full life cycle emissions of producing the cars, trucks, boats, and airplanes in the first place.
Also, I think it's worth pointing out that the sectors you list are like 1.5 to 2x larger than the one he gave and the largest nondivisble sector, you listed is literally 10x, which I think does more to prove his point than yours.
Also, by your logic, literally any new sector of the economy that uses any amount of energy, basically at all, should be banned, because it "all contributes." that's a consistent position to take and there are certainly people that hold that position, but that at that point seems like a fundamental axiological difference that I and probably OP are simply not going to agree with you on.
Thats OP's point - you need to reduce usage everywhere and pointing out that AI is only 1.5% doesn't take away from the fact that usage needs to be reduced there as well.