I started a thread here about a year ago to observe artists who are vegetarian or vegan. But here are a few songs with an explicit vegan or animal rights message:
Late 80s/Early 90s alternative (probably the first vegan song I heard as a child, I liked the animal sounds) -
Late 80s/Early 90s straight edge hard core scary vegan punk -
80s Animal Rights anthem, a guy at my high school used to wear this tee shirt, for years I thought Morrissey was vegan but found out that he was actually vegetarian and only became vegan in the 2000s -
Rise Against is one of my favorite over all political bands from the 2000s but this is their most explicitly vegan song, although all members of the band are either vegetarian or vegan:
The animal rights theme in this 2000s song by vegan Moby is in the video rather than the lyrics of the song -