By GENERAL definition: Rangers = Protestant, Celtic = Catholic......whilst this isn't exclusive it is historically accepted that this is the identity of the two Clubs............the context of the use of the word h*ns has correlated with Rangers and therefore Protestants and likewise with the word t*m and Celtic and therefore Catholic.
Personally I don't give a fcuk as I thankfully support neither team nor care for any Religion (whilst respecting the right of those that do so)
An example of this (albeit in a racial not a sectarian way) is the N word which is factually the Latin word for black.........through the annuals of time the use of this word has taken on a derogatory and racist context and is no longer acceptable to be used in modern society. The Latin word for balck remain the N word however.
I have never heard the term "neep" and am therefore unaware if it is offensive or not.......feel free to enlighten me as I won't be offended as that would suggest you (or any internet forum random for that matter) bared some importance in my life.