So you guys are saying you know better than the men closer to the Apostles, the men who drew up the creeds and wrote the theological texts?
The men who read the Bible in its original languages?
You know better?
I would argue that modern scholarship understands the Bible better than the church fathers did, yes. Part of that is, ironically, because we now know that the apostles did not write the gospels, which is something the church fathers assumed somewhat erroneously.
We also have a better grasp on the ancient language than they did, because they lived several centuries removed from the texts' original context. It's only through putting the texts in their proper historical context that we can begin to fully understand them, and this means that we can't make the same assumptions that the church fathers did from their perspective that was tainted by several generations of constantly morphing early Christian tradition.
We can read the Bible in its original languages today, too.
The only argument that can be had in favor of these creeds and doctrines is the one about tradition. There are many religious arguments in favor of a unified church tradition, centered around apostolic succession, guidance from the Holy Spirit, and divine providence. Without an affirmation of these supernatural elements, which are later constructs that are not really Biblical themselves, the idea that these creeds have any serious weight begins to dissolve rapidly.
I think we should press even further and ask why such a supposedly enlightened counsel canonized forgeries, such as the fake letters from Paul or the illegitimate Gospel of John. When we realize that this canonicity isn't based on a solid understanding of these texts and their origins, we also have to ask what other early Christian texts we're glossing over simply because they weren't canonized. How many modern Christians have read the Apocalypse of Peter? How many have read the Gospel of Thomas?
Once you start pulling that thread, everything unravels. The entire legitimacy of a Christian religion in general begins to flounder. Do we even know how much of the gospel accounts actually resemble something a historical Jesus taught? There's no academic consensus on the matter.
The church fathers weren't even aware of most of these issues. They didn't have the information and tools available to modern scholars and they were more concerned with preserving a genuine Christianity, which unfortunately assumes that there is a genuine Christianity to preserve. There isn't.