Question

まかろん

画像はミルドレッド（黒人）とリチャード（白人）の結婚や生活が認められず、2人が裁判を起こしたことに関する文章です。

赤でマークしてあるところで、なぜ過去完了形が使われているのか分からないため分かりやすく教えてください🙇🏻‍♀️

On June 12, 1967, the court handed down the final decision. "Under the Constitution,
50 every person has the right to marry someone from another race." Mildred first heard
about the decision through a phone call. Grasping the phone tightly, she remained silent
for a while. She was too happy to say anything. They had won! That was the day when
mixed marriage became legal everywhere in the U.S.
Mildred and Richard returned to Virginia with their children, and lived there happily.
55 At last the Lovings had truly and legally become a "loving" family.
(688 words)