If you know Faith No More, you likely know them from their later stuff. This song, however, was one of their first - featuring a different lead vocalist than you might recognize.
The original lead vocalist and principal songwriter was a man named Chuck Mosley (who passed away of a presumed heroin overdose in 2017). The lyrics for this song were written by Mosley and Roddy Bottum, the latter of whom also had a hand in the music.
This version, the best known, is from their 1988 album Introduce Yourself, but was originally recorded for their 1985 rare debut We Care A Lot. At this time, you can really hear the Bad Brains influence on the band - very bass-heavy, very activist.
Now, compare that to the harder, sparser version from their 1985 debut. Yes, lyrically, it's a little different, but the musical differences are actually more apparent here - with a more drum-heavy mix going on here.
Mosley left the band soon after - some say he was fired, but it seemed to me to be more of a creative direction thing, as Mosley wanted to do less hard rock and more acoustic stuff. Bottum has characterized it as "fired without being fired" and somewhat amicable.
The band did not abandon their best known early song, though, and released a live version of the song in 1991 as a single, with Mike Patton on vocals. It's a different song, and Patton does a lot of ad-libbing while trying to hold onto the legacy of Chuck Mosley.
The band did eventually break up, but reformed with Mike Patton on lead vocals - and of course they still perform this song (as they did here in 2015), which still carries the anger and activism Mosley and Bottum wrote in 1984.
By the way, anyone questioning whether or not the Mosley departure need only look to this performance from 2010, which featuted him on vocals with the band performing several of his songs, including, yes, "We Care A Lot".
Here he is with the band AGAIN in 2016, a year before his passing, performing the song and others from their reissued debut,. He sounds great (and looks awful).
As far as we can tell, that's the last time the band has performed live, although they've scheduled other shows that were cancelled.