The “word protestant” didn’t have to be defined. God knows who are His and who aren’t. Contrary to popular opinion, they don’t need to be labeled for Him.
Sure it did, Catholics had to have a name for those who claimed to be Christian but instead of following Christ, followed such as Luther, Zwingley, Henry VIII, Wesley brothers, Storch, Simons, Knox, Brown, Smyth, Michelis Jones, Fox, Amman, Lindley, Otterbein...etc One must have a way to identify all those various "true" DENOMINATIONS, VS:true Catholic Christianity..........see how well it works?