Do they still allow Rangers fans to sing “We Are The Billy Boys” at matches?
Not really.
Its been banned at Euro matches, and the Scottish league is ready to clamp down on it, so whilst you will still hear it, it has virtually disappeared.
The irony is that the sole offending remark refers to Fenians, and the song is talking about the actual Fenians, but over the years, too many Rangers fans used that term to refer to Catholics, so the original meaning was lost and thats why its offensive to many people.