The alternative, having literally thousands of small groups with unique doctrines, is more problematic IMHO.
I mean, we all have thousands of different individual beliefs, right? Having set, relatively inflexible beliefs without much wiggle room historically sets up a split, IMO. It's like building a bridge without compensations for the expansion/contraction of the structure or lateral shifting. It's pretty strong, but as soon as turbulence arises, it has no way to deal with it and can only fracture. It's not a perfect metaphor, but it's pretty good, I think.
I see standardized doctrines as guidelines. I mean, I've yet to find a single church, group, or denomination that I can say that I agree with more than, I dunno, 70% of the time. That doesn't mean that I can't attend a church, but conversation is seldom as constructive as it could be if both parties didn't make the assumption every time that certain tenets were inflexible. Now, I know this is a bit of an exaggeration--most reasonable pastors/priests/ministers are not going to shut down and say "nah, this is the doctrine. you can't question it", but at the end of the day, it generally comes down to them saying that in one way or another because as a minister in X denomination, they preach Y.
Of course, that doesn't mean that I have to quit because of this, but I just glean a whole lot less from a sermon when I can only listen to such-and-such doctrines without reciprocal engagement. I've been lucky at different times of my life to be able to attend a church that would have small groups through the week for discussion of topics covered in sermon, but this isn't always the case, and sadly I had to leave a recent particular church like that when I moved from my hometown. I guess right now I'm in a weird spot where I haven't found a great place (yet) that is truly challenging or engaging. I acknowledge that it's not a universal experience, though. For many people the modern church format works well enough. I guess I just wish there was more out there for those of us who don't prefer it for learning; I guess that's where sites like this can come in.
There's a little saying that goes "Catholics claim the Pope is infallible, and nobody believes them. Mormons claim the Prophet is not infallible, and nobody believes them." What that's talking about is the Prophet is considered to be completely reliable in matters of doctrine, but even then it still has to be something agreed upon by the entire First Presidency (The Prophet and the two counselors) and, I believe, the Quorum of Twelve. (Apostles) Sstavix might want to correct me there if I've stated something inaccurately. It isn't that Prophets can never make mistakes as leader of the Church, (I think Brigham Young dropped the ball more than once) but even so the Lord won't allow the Prophet to lead the Church astray in matters of doctrine. For the First Presidency to come out with some new doctrinal idea us relatively rare compared to, say, matters of more ordinary Church policy or management, which can often be matters of personal judgement.
I think that's similar to the Pope, in that he is also only considered truly infallible if he's speaking Ex Cathedra (A very formal and official declaration)
So I guess to illustrate, the Prophet can certainly be wrong if he expresses something as his own opinion. If he says "I think the 49ers are going to win the Superbowl" nobody thinks he's saying that God told him so, but if the First Presidency comes out and says that, as a matter of doctrine, homosexual behavior is sinful in the eyes of the Lord, then it is so because it needs to have come from God.
I guess this is one of those fundamental principles that I'm just not on board with. It isn't that I think you're flawed for believing it, and I can see exactly why you and many thousands and thousands of others find it to be sound, and I'm not criticizing you for believing it--just to be clear.
I just don't feel that in terms of spiritual matters, that it's necessarily constructive to have someone make sweeping statements in an ex cathedra
manner. I don't know exactly what makes a revelation to that guy (pope, prophet, what have you) more valid that a personal revelation to myself. I know there are systems set up for qualifying these people, but it's all just so subjective. Many would say it's a pretty solid setup and many would say "ehhh I don't know how I'm supposed to just trust that. I'm gonna determine doctrine for myself, thanks." I just fall into the latter party. I still listen, engage, take careful consideration of the advice of various resources and theologians more intelligent than I am, but at the end of the day I don't defer to a set standard. I just have too many disagreements on some interpretive/intellectual level to default to a denominational set of doctrines if I'm not sure about something.