raptorattacks

Quoting from the red cross FAQ:

The waiting period is required due to these drugs interfering with viral replication and thus possibly altering the detectability of diagnostic and screening tests for HIV, including extending the window period prior to detectable infection or a delay in producing antibodies.

...

The Red Cross and the FDA support individuals making responsible choices for their health and the broader health of our communities. The Red Cross and FDA are involved in ongoing research, data collection and assessment related to transfusion safety, including the use of HIV preventative medications, and will continue to seek opportunities that could potentially help lead to additional changes. The Red Cross does not encourage individuals to stop taking these medications in order to donate blood.

Just discovered these rule changes based on your comment. Unfortunately my partner and I still can't donate blood (they're on PREP, and I was in a vaccine trial that disqualifies me), but it's cool that they've finally eliminated the worst of the queerphobia in the US.

I experienced the reverse of you - as soon as I transitioned I was disqualified as a trans man who has sex with men, even if the sex was identical pre- and post-transition. These were the previous "updated" rules that were supposed to be less queerphobic, but obviously weren't hitting the mark.