The exact same schoolyard game as "kill the guy with the ball" (aka "Smear The Queer"), only the name is changed when played at Catholic schools. A comical way of encouraging a bygone era of sectarian rivalry in Christiandom via youthful bravado. Especially popular in Irish communities. Has NOTHING to do with anti-LGBT bigotry.
Hey Bill, want to play Beat the Protestant with us?
Sure! Just make sure the mother superior doesn't see us rough housing.