How so?
What do the major historians of Protestantism say? Like almost all their colleagues, John Dillenberger and Claude Welch link the origin of the word Protestant to the Protestation of the German evangelical estates in the second Diet of Speyer. But they see in that term the duality of protest and affirmative witness. That protest, they write, wasfrom the standpoint of affirmed faith. Few churches ever adopted the name Protestant. The most commonly adopted designations were rather evangelical and reformed. ... [W]hen the word Protestant came into currency in England (in Elizabethan times), its accepted significance was not objection but avowal or witness or confession (as the Latin protestari meant also to profess).That meaning lasted for another century, say Dillenberger and Welch, and it referred to the Church of Englandsmaking its profession of the faith in the Thirty-nine Articles and the Book of Common Prayer. Only later did the word protest come to have a primarily negative significance, and the term Protestant come to refer to non-Roman churches in general.-- from the thread History Lesson: Positively Protestant
They continually seek to reform, really reestablish, the Church of Christ (oops, cannot use that name, already taken, along with thousands of other names ... ) because their premise is that the LORD Jesus Christ did not build his church upon a rock that withstood the gates of hell in a public, powerful, and historical witness to the world. Every denominational split amongst mainline Protestants bears witness to nature of the movements. Do you really want to make the argument that your denomination is the holy catholic apostolic church founded on Messiah by the Apostles (and the rest are in some kind of error) ? Do you prefer to argue there is no holy catholic apostolic church in existence on this planet ? Or that diversity of doctrine is good because it let's freedom of the individual rule in a cafeteria style of live and let live prosperity (oops, that word is already claimed too) . The so-called Hebrew Roots Movement is another example. Do you want to argue all the Gentiles got it wrong until now ?
That is the fundamental problem.