I can’t believe a split is being risked over this issue of all things. Gun Control is not needed if people’s basic necessities are being met; security of all sorts, health, happiness, and social connections, etc.
You're in no place to lecture anyone else on causing needless division. Also leaving aside the merits of having it in the party platform, the number one necessity is life and safety so gun control is relevant to that.
In that case, I'd like to see you adding support for banning abortion to the Labor platform.
Murder using guns is already a crime.