It is a stupid logical fallacy that HRT leads to suicide. In fact, the increased rate of suicide among transgender people is due to the fact that HRT does not feminize them enough to make them feel comfortable in their bodies. Their dysphoria continues, and this hopelessness causes suicidal thoughts. However, HRT actually reduces the risk of suicide in transgender people because it reduces dysphoria to a tolerable level.
But idiots incapable of logical thinking saw the statistics about the increased risk of suicide among trans people as a good argument against HRT.
Estradiol itself is not capable of causing suicidal thoughts, otherwise women would commit suicide en masse.
If someone commits suicide on HRT, it is only because they did not get the desired effect.