If you have “rarely seen” Protestants correcting or disagreeing with each other you haven’t been paying attention or don’t know who claims to be Protestant. I, for instance, have had many contention with others who claim to be Protestant. As an example those who claim to follow Luther or Calvin. Then there are those Protestants who claim the church has replaced Israel or who are from the prosperity school of thought. There are many, many disagreements and debate amongst Protestants.
The Churches of the reformation disagree on relatively minor issues, like siblings in any family. However, we are unified in Jesus, we all saved by Grace only, thru Faith only, in Christ only. We are not concerned with carbon copy uniformity on issues where the bible is silent or vague. Non essentials are..... not essential.