Highroad to Nowhere?

A former astronaut has apparently criticised the Virgin Galactic concept for 'space tourism' as merely 'dangerous dead-end technology' (https://www.theguardian.com/science/2018/dec/18/richard-bransons-virgin-galactic-space-flights-criticised-as-dangerous-dead-end-tech) pointing out that they are essentially high altitude flights that fall rapidly back to Earth. I am, surprised, however, that no one seems to point out that they would be a prominent addition to greenhouse gas emissions.