Protestantism is to be discarded altogether because its unifying principles of sola scriptura and sola fide are wrong. The poor works of some members illustrate why (1) the aforementioned principles are weak foundation and (2) the claim of divine leadership is often hollow and altogether a poor, illogical argument.
What do the poor works of the Catholic Church illustrate ... ?
That Catholics are human. The difference is that all these grossly heretical Protestant denominations — that marry gays, or allow abortion, or praise greed — derive their heresies from sola scriptura and sola fide. When a Catholic fails at something he does not start a denomination whereby his failure is proclaimed a good thing. When a Protestant fails at something, chances are he can find a denomination that fits his failure, or if not, start his own.