The alleged infringement in this case is an extremely common chord progression. A victory for the Gaye estate in this case would have a disastrous impact on the music industry writ large. As unlikable as Ed Sheeran is, you don't want him to lose this case.

(the Gaye estate has pulled this shtick before when they sued Pharrell and Robin Thicke over "Blurred Lines," and while I despise that song, it had a similarly deleterious effect on music)