no, it wasn’t “more data”, it was just data. blood letting and mercury are pre-scientific treatments that were in use during the 1600s. puberty blockers were developed with a modern understanding of hormones, and extensively tested before they saw use in a clinical setting. you might as well have brought up magic as a legitimate medical practice that we eventually proved wrong. like, no duh, but it also has basically no bearing on the safety of a chemically synthesized hormone inhibitor invented in the 20th century.