Fair? Maybe not, but IMO it doesn't matter. The only thing that matters is gross emissions. The effects of a warming planet will not be fair. We should be looking to reduce/eliminate emissions wherever they are happening.
Why aren't we?
[0] https://www.theguardian.com/world/2025/nov/11/china-co2-emis...
[0] https://ourworldindata.org/grapher/annual-co2-emissions-per-...
Which is why, unless you can come up with a good argument that some people have some kind of divine or natural right to a bigger share of whatever global emissions budget we decide we need to stick to, per capita is the correct way to compare countries.