Also, it's worth pointing out that the source of regret is... people being jerks. Upon transition, transgender people often lose the support of their friends and family, and endure abuse by the public at large. The anti-trans community is abusive and repressive, and they (if indirectly) point to the results of those efforts as a reason not to transition.

https://pubmed.ncbi.nlm.nih.gov/9570489/