The statement that there is only one way is correct in my humble opinion, you can't get to God without going through Christ. Christ is the only way. I think most will agree to that but that is about the end of agreement. There are so many different views on what is the right the way to Christ that causes the problems.
I think immediately of the first centuries of Christianity and the big fight between Arianism and Nicean Trinity. For a couple of centuries and a century after Nicea there was not a conclusive standard on the Holy Trinity. The west were pretty much Niceans and the East were pretty much Arianist. The big difference is that Niceans taught that Christ and God were both Eternal Gods and actually the same God while the Arianists taught that Christ was the Son of God and although still God he was a subordinate of The Father.
The Bishop of Alexander, a good friend of Constantine motivated Constantine who while not a Baptized Christian chose what we now call Nicean Trinity. It was not the last word but about 100 years later actually became the last word at least as far as the Church of Rome was concerned.
In those days churches were much more autonomous than today. Constantine's whole idea of calling a council at Nicea was to get some conformity in The Christian Church. There were simply no authoritative standards after the Apostles and those that walked with them all died off.
Were the Anathieans so horrible that they had to be excommunicated? Then the Anathieans were in charge were the Niceans so wrong that they had to be excommunicated?
After Luther again we have very religious people finding different ways to get through Christ to God. After Luther other non-mainstream religions sprang up that said if the only way to God is through Christ then it doesn't make sense that God and Christ are the Same. It would be like saying you have to go through God (Christ) to get to God (God) or like saying you have to go through God to get to God.
So what to do. We are very fortunate on the one hand that The Holy Roman Catholic Church has preserved the Bible we now have but perhaps unfortunate for the many books that were lost to the burn pile of Nicea and beyond.
Who is the one person who speaks for God on the earth? The Pope? The Patriarch? Someone else like John Denver(RIP)? Inquiring minds want to know and I personally don't t believe that because you can't figure it out that you will go to Hell.
I'm not stupid enough to think that what I think matters to anybody but me but after all that is what counts to us as individuals. I think if you are truly looking for Christ to get to God then you will get there.