I won't engage anything you said until you revise that outrageous 75% figure. I was Russian Orthodox for ten years before I abandoned Christianity, and I was a Roman Catholic for twenty years before that. I am not a fool. I also know what Roman Catholicism preaches, and I find much of what you said suspect. But again, no discussion until you are more honest about demographics...
Oh, but what I said about demographics IS honest.
Latin America, much of sub-Saharan Africa, the plurality of Canada, a quarter of the United States, tens of millions of Indians and 100 million Filipinos, and 2/3rds of Europe (France, Iberia, half of Germany, Belgium, Italy, Austria, Croatia, Poland, the Czechs, "Volhynia" are all Catholic. So are the Lebanese Christians. That's about 1.4 billion people, more than China. Catholicism is the largest religion in the United States and Australia as well.
Over against that you have what? The Orthodox are the next biggest group, but what is that, really? Less than 10% of any of the Middle Eastern country, dwindling down to 5%, 4%, 2%. There's Ethiopia, with a few tens of millions. Mainly there's Russia, with 170 million people (not all of them Orthodox) and much of the Balkans. The Orthodox make up perhaps 10% of Christianity.
And then finally there are the Protestants, which can be divided into two groups: the Anglicans, a sort of Catholic-lite version, that is more than half of them, and the rest.
If you go look at the figures, it works out to a Christian world of about 1.9 billion, 1.4 billion (over 75%) of whom are Catholic, another 10-15% of whom are Orthodox, 5-6% are Anglican, and the remaining 5% or so, the welter of Protestants, Mormons, Jehovah's Witnesses, etc.
My figures were right the first time, and I will not revise them. The overwhelming supermajority of Christians in the world are Catholic, and the most important minority of Christians is Orthodox, which are almost Catholic is most ways.
If you're going to speak to "Protestant Christianity, the 10% fringe, by all means do so, but don't elide that into "Christianity". Christianity, by and large, is Catholicism.
As far as your "suspicions" about Catholic beliefs, have you ever read the Cathechism, the Canon Law, the Bible and a good volume of the Lives of the Saints cover to cover? No? I have. Of course what I say, or anybody else for that matter, emphasizes the aspects of the religion that I think are important for the discussion, but I don't simply make things up.
When it comes to the Bible, there are only a few portions where Catholics are bound by the Church to a certain belief. Beyond that, Catholics are quite free to read and interpret, just as long as their interpretation doesn't break any of the infallible doctrines - which are mostly contained in the Nicene Creed.
So, if you don't want to have a conversation, we won't. Certainly if the "condition" of having a conversation with you is that I revise basic demographic figures or cease to state that Catholicism is the supermajority Christian religion, I'm not going to lie in order to have a discussion with you. That game ain't worth the candle.
Instead, I will just let the Catholic supermajority fact worry you. If you want to go research it to "prove" me wrong, go ahead. If you come back triumphantly and declare "Ha! Catholics are only 73%, not 75%!" I will still be right. 73% is still a supermajority.
If the numbers madden you, go research them and struggle with them. Once you look and realize that, yes, Catholicism IS supermajority Christianity, then you can come back and start quibbling about doctrines. You'll discover that what I've said is the truth there too.
Then you can be miffed that you can't play the same game with Christianity writ supermajority large that you can with little splintered and squabbling sects in the 5% fringe.
And then perhaps you will come to a more mature and reasoned viewpoint of Christianity. Catholics don't play Sola Scriptura, because it's not true.