The subject of the first few chapters of 1 Corinthians is Paul’s concern about divisions in the church. It takes him only nine verses of introduction to jump right into it, and because it is the first of many different church-related exhortations in his letter, we may reasonably infer that the apostle viewed the matter as very significant.
The fact that the churches down through the centuries have pretty much entirely failed to process the lesson he was teaching and put it into practice in no way diminishes the importance of what Paul said or the clarity and intensity with which he wrote about it. Expressing the unity of the body of Christ in every possible way on every possible occasion is a mark of mature Christian faith. More, please!