The IBA changed their policy and that excluded these male athletes last year. However, the IOC changed their policy to stop sex testing in the late 90s to allow male people who were 'assigned female at birth' to compete as female.
Why? Because of purely emotional reasoning based on philosophical principles that guide inclusion.
The IBA did extensive testing according to their press release over night. The testing found that these two boxers had physical advantage. They cannot release any more details other than that.
The last two Olympic boxing competitions have been run by the IOC due to corruption uncovered in the past. Therefore the IOC regulations are the ones that are used. The IOC declared that all sporting federations should decide the policy for participation on a sport by sport basis. But then ignored the IBA regulations.