Not applicable. Almost every Christian adheres to (... or rather, is supposed to) an explicit ruleset created in the New Testament along with some additional axioms carried over from the Old Testament. Each denomination has specific interpretations (by man) providing a strict ruleset, but obviously, there can be only one truth with regards to God's and Christ's intentions, and most denominations declare their ruleset follows that intent. For example, some denominations have rules where phrasing that last sentence as "God's and Christ's" would be blasphemy, and there would be no room for interpretation because their men have interpreted the intent of God's and Christ's intent in that way. -But most denominations have liberalized over the years, some even becoming secular/"non-denominational," conceding morality in exchange for a larger member base accepting a vague, flexible - useless - ruleset.

As I was raised, a Catholic wouldn't be considered a true Christian because of their repeat violations both explicitly in their laws and implicitly by actions done in the name of Christ (rather, the Pope and, in older times, government controlling the pope). They've scrubbed Christ's words for their own ends and functioned as an authoritarian, militant government with some ridiculous claim that they have the authority to kill people before living through their natural life and possessing all opportunities to accept their obligations as was intended by God. They're considered idolaters who insist on putting decadent false prophets before Christ, and are necessarily disconnected from the message of Christ. I mean -- forget Muslims, Jews, Sikhs, Confucians, and Buddhists, because these Catholics are running around like wolves in sheep's clothing who all need to be explicitly excommunicated - at least everyone else has a different ruleset. -but I was raised Baptist (really, Anabaptist) with a strong iconoclast sentiment pounded into us where a church owning property is itself a sinful act. It's not "no true Christian," it's "here're the rules you've institutionalized violation of, thus becoming a puppet of the devil." There wasn't some exhaustive text on what kind of ideas and rules you had to accept to be a Scot, but there are exhaustive texts on what you need to accept to be a Christian.

Incidentally, I haven't fully shaken Baptism from my own code. I found myself mildly offended when a great-aunt-in-law "baptized" my daughter when she was an infant (she didn't realize she was seen), not because my daughter was being involuntarily associated with stupid Christian rituals with absolutely zero effect, but because it made a statement to God that she accepted Christ and His ruleset without her being able to declare it herself. It's like a government forcing someone to be a citizen because they were born in a certain location. -Like, she can't even speak and you violated her sacred obligation as a creation of God (which, by God, only she has liberty to reject or accept) -- the very idea that a Catholic implies they have God-given authority over my daughter's soul offended me, as well as being offended on God's behalf since I was raised to be very sure this was an explicit rule violation. I know it's dumb as Hell, but it initially struck me as a rule violation which'd piss God off, because now if she wants to make a commitment to adhere to Christianity, she has to reject the Catholic soul-fascism at her real baptism, which means I have to talk to her about why her great aunt is an unwitting agent of Satan.