Why is the US not on the UK Green Travel list? [Forbes]

Interesting reporting from Forbes, " It is bad news for the U.S. which hasn't been included on the U.K.'s safe list this time, particularly after recent reports that a bilateral agreement to restart travel between the U.S. and the U.K. was in the pipeline. The Telegraphreported that according to its analysis of U.S. data it should be in contention to join the new U.K. safe list." Forbes https://www.forbes.com/sites/alexledsom/2021/06/24/uk-announces-new-travel-safe-list-but-not-to-the-us/