I’m not doubting that you believe in God. My point is that if the priesthood could prove the existence of God to everyone else, we wouldn’t be having this debate.
And again, that's invalid. Even if a priest could prove to us that God existed, and existed as the Father, Son, and Holy Ghost, forever and ever. The Whole Nicene Creed, blah blah blah. Amen. It still wouldn't matter. We'd know who God was and a lot of what God said to do, but Jesus didn't pronounce on "everything". Nor did the Prophets, even if part of their details weren't overridden. You will come a great distance to closing the gap if you end up in believeing in God in that manner, but it doesn't answer all questions. Debate on doctrine is still possible with sure knowledge of God's existence as a fact. Homosexuality is one such doctrinal decision.
Okay, but then how do you know when to listen to someone who says he’s going to “clean it up?”
Well, at the time, it would have been obvious. Jesus was there and was doing miracles. That's a relatively good indicator that you should pay attention.
Now, really all that matters is that if we stipulate that Jesus could tolerate association with what he evidently considered an imperfect institution without renouncing it, ie Judaism, that logically, it is not inconsistent that He could tolerate continued association with a similarly flawed present institution, ie. The Church. If we then stipulate that Jesus is God, for this example, then logically it follows that God can tolerate association with a flawed institution.
Of course, this is obvious, since God would have had to deal with flaws all day long if He's dealing with us at all.
As for the rest....
...let's just shrink this a bit, since the questions are starting to get so precise on wording that actual word choice is motivating some objections.
Your questions seem to revolve around the emerging points of:
a.) You should make your own decision on your own religion.
b.) The decision you make is a personal one and no one can tell you you're wrong if you believe that, because they don't know anything any better than you do.
Re: A: You, as a human, have free will. No Christian can legitimately deny this. If you are a Christian, you are that way because you decide to be. A Muslim or pagan forcibly converted to the faith is not a true Christian unless they take on that faith themselves. Granted, there is infant baptism in some sects, but there is always a confirmation process when you've obtained an age where you can be fully held responsible for your own decisions. Some groups have adult baptism and may combine the process. I'm not up on what every little sect does these days, but Christian = voluntary belief.
Thus, all Christians believe that you make your own decision as to the religion that you choose. Not only that, but you *must* do so in order to follow Christianity. While the deck might be stacked in favor or against the prospects of acceptance, the ultimate decision is always personal or it doesn't count.
Re: B: While your ability to choose is your right and responsibility due to free will, that does NOT confer upon you the inherent ability to make correct decisions. If I believe in God and you abide by your particular brand of Wicca or Islam or atheism or whatever, one of us, or none of us, are going to be correct. Some beliefs can co-exist, but many do not. And, of course, co-existence is no guaruntee of correctness either, since complete co-existence in all cases means you really either don't know what you believe or what you believe is so general that it really doesn't serve any consistent purpose in making decisions anyhow.
Obviously, there is a key factor in all free will situations: having not only the ability to choose a path, but also the knowledge that a certain path actually exists to begin with. That is what I mean when I said that you can decide what you want, via free will, but that ability to decide is limited in and of itself. Chances are that pure free will isn't going to lead you to the right path without significant errors along the way because otherwise it would no longer admit of any doubt or other options, and thus, would cease to be free will by defintion.
In short, personal decisions on your own morality part of the equation, but aren't enough alone. Revelation is the key part of the equation in this regard, because it does present the options you need to make the right decisions and properly employ free will.