30 year old cases can and do result in convictions, even if it is a "he said, she said"-type scenario. The fact that she had contemporaneous notes and inconsistencies with Porter's recollections only strengthen the argument against him.You are aware she withdrew the complaint? It doesn't make her any less believable, but makes it kind of hard to get a conviction since she and Porter are the only eye witnesses.
(For me) the issue is not as much the allegation of rape, but the government cover-up/brush over and opaqueness of what is going on behind the scenes. Governments get up to all kinds of sh*t including abuse of power, so they need to be held to account.