You haven't given the number of how much CO2 people use to live, only what the sustainable number is, so there isn't enough information to make any conclusion.
Sounds like that number just takes the CO2 that the us produces and divides by population. It would be agreeable if the wealth that came from that CO2 production did also was similarly distributed, but since it's not, that's not really how much your every day joe produces to live. It's what is produced to put another billion dollars onto a company's books.