Most people are swayed by apologists who claim that their systematic theology is consistent within itself.
Consistency is appealing to many people. Common sense can detect when statements are contradictory. Apologists would point to the Law of Non-Contradiction, that it is not violated by their theology, and so on and thus it must be true. So laymen are easily sucked up by such propaganda.
Do not get me wrong, consistency is very very important and it must exist in a system. However, it is not enough. It is a necessary condition but it is not sufficient; and this is where the unsuspecting Christian gets rounded up. They get rounded up because they look at consistency syntactically, and not semantically.
When it comes to TRUTH, consistency is not enough. Rather you must demonstrate a world wherein your statements are true (in logic, this is called a model).
All unicorns are horses that have one horn.
Silver is a unicorn.
Ergo: Silver has one horn.
This is good syllogism, and it is consistent, valid reasoning. But this is not yet true. We must demonstrate there are indeed unicorns. We must demonstrate also there is a unicorn named Silver. So where is that world?
The name calling in Calvinism/Hyper-Calvinism or Arminianism/Hyper-Arminianism etc happening in the Evangelical world hinges on the concept of consistency, but consistency is not enough.
Consistency is good, and it is mandatory, we will not accept any less, but the question with consistency is this - consistent with what? With philosophy or the Bible?
This is where I find Lutheranism different. It has no shame, no insecurity and no sense of guilt when it is not able to answer certain questions. Faith does not always have the answers, it believes what the Scripture promises even when the senses say otherwise.