Many protestant Christian can't even tell the differences btw the denominations
Where did you get this info from?
I don't think they study the reformation correctly.
If they did they most likely would stay Protestant, the reformation was triggered heavily by the practices such as indulgences essentially, by purchasing an indulgence, an individual could reduce the length and severity of punishment that heaven would require as payment for their sins, or so the church claimed. Buy an indulgence for a loved one, and they would go to heaven and not burn in hell. Which the reformers disagreed with which set off the Thesis. Practices and The authority Rome had caused the reformation.
By correctly I mean they should have read how the reformation is going back the early teaching of the church.
What do you even mean by this? What does the reformation gotta do with The early church? The early church traditions and scripture authority was the main reason for the reformation, Martin Luther and John Calvin both believed in church tradition but believed scripture as primal authority have you read they works before?
If someone claim he's a protestant, he/she must be well educated of church history and have read the church fathers.
This statement just is very ignorant in itself, you dont need to be well verse on church history and still affirm the reformer theology. Not every Christian need to focus on Church history.
I've seen too many protestant Christian defend the teaching of their church, yet ignorance about the writing of the early church and ignore the teaching of other protestant denomination leaders.
Ok so? Are they supposed to?
If that's the attitude of working out our discernment, we can easily fall into a cult or believing a new religion.
Dont think so, most of the time Christian denominations that are not the majority stem from ideals that are not really from the Protestant councils and synods, and teachings of the reformers most of the time those beliefs stem from
Solo Scriptura(Scripture Only to determine everything)vs.
Sola Scriptura(Scripture is primal over tradition on means of faith). We wouldn't be so ignorant and say we would fall in cults if we all have read the canons of the council of orange, the 95 thesis, and the Westminster confession(Also the mainline Protestant denominations has catechisms).
Side Note: Not all Protestants need to be well verse on history to refute common Papal claims on there faith.
Btw: Im Orthodox just showing that this thread is very disingenuous and a very opinionated position.