They are agenda-driven and their agenda is their “witness”.
Oh, they have an agenda alright. It isn’t a witness to Christ, however. No one who wants to witness to Christ would just make things up, for instance.
Anti-Catholic Protestants are a strange group. I have met and encountered plenty of such people and they often seem like regular folks in every way - until the Catholic Church comes up. In an instant they change from normal people to hate-spewing, lying, conspiracy-theory-spreading, ignorant, bitter, mean spirited wackos. No distortion of Catholic doctrine is thought to be too much, no twisting of history is thought to be too wrong for them to do it and throw it out there as if it were all true. You can catch them lying, it won’t matter. You can prove that what they’re claiming is impossible - it’s just absolutely untrue - and it still won’t matter. They don’t care about the truth when it comes to the Catholic Church.