Although I agree that the intro to Stairway to Heaven was eerily similar to the other band's song; there are many many songs out there that sound similar to each other. There is no getting around this altogether. As long as they are discernibly different I do not see the problem.
Though the jury finds that Led Zeppelin did not steal the introduction to' Stairway to Heaven', it seems too similar to the other band's song. In a brief passage in 'Taurus', the instrumental from the 1968 'Spirits' album, the notes do sound similar to the opening part of Led Zeppelin's 'Stairway to Heaven' which was released in 1971.
I believe that the jury was correct in handing down its verdict regarding the Led Zeppelin song, Stairway to Heaven. The song and its introductory melody is substantially different, and it does not take a highly-trained, musical ear to hear the difference. Good job by the jury in this case.
While there are many possible combinations in music, the way music is written makes it easy for one riff to sound like another. Music and art borrows from and is inspired by each other, and much of what is borrowed is not as unique as some record executives and copyright holders try to pretend.