Ultimately, Paul is not critical of the fact that there is a celebratory meal taking place. That is not a fundamental issue. Paul does not necessarily rail against the institution of the symposium or the convivium itself, nor does he express opinions on the nature of eating and drinking (or what is consumed), except when he enters into a dissertation on practices of eating that are rooted in the need for the community to operate with a compassionate and self sacrificial love and sensitivity.
Clearly though, with the symposium in view, he has concerns with some things that take place at this portion of the meal. However, he does not appear to have a desire to alter the fact that it takes place. Rather, his concern seems to lie with the fact that love, and the preferring of one another that will come with the modeled-out love of Jesus, is not being shown forth through the various activities that lie within that view. It appears that Paul, understanding the example of Jesus at meals, while tying in the messianic banquet (rule of God) aspects of Jesus’ meal activities, sees the tremendous importance of the meal---especially as a force within society. Consequently then, he wants to see this powerful force re-shaped in a way that will cause it to reflect the priorities of the kingdom of the Creator God.
The more damning aspect of the activities of the church is that, with the powerful social forces that are at work, this church seemed to be participating in activities at their meal and related symposium, with those activities maintaining and expressing the requisite social stratifications and divisions that one would expect in that day, but which were clearly verboten for the church of the Christ. In this way, this church has made their celebrations (meal and symposium taken together) indistinguishable from any other such celebration that might be taking place in Corinth.
To make matters worse, they are doing this while they referring to what they are doing as the Lord’s Supper, and thus by extension pointing to it as their own version of the messianic banquet. This is highly problematic, especially if the very forces that deface and defile their God’s creation, and which dishonor and defame divine image-bearers for the pleasure and amusement of another set of divine image-bearers, are on display.
If the honor system was in effect in an obvious way at this church’s meal table, then this was going to be a problem for Paul. If the “first” were making sure that they were still first and recognized as such (possessive of more honor in the court of public opinion and so getting all of the food and drink that they want, or getting the best), while also making sure that the “last” were still recognized as being the last (possessive of less honor in the court of public opinion and relegated to receiving the leftovers or the worst, if anything at all, which was standard operating procedure for the meal tables of that time and place), and if they were doing so within the event that was supposed to be a tool that would mark them out as being a very different community in which preferring one another was the order of the day and in which the first shall be last and the last shall be first (the shameful/humbled being exalted and the exalted/honored being humbled---a flattening out of society in which there was neither Jew nor Greek, slave nor free, male nor female, but in which all were one in Christ, which was the vision of the messianic feast that marked out the time that the Creator God did indeed rule on earth), then this was certainly not the Lord’s Supper, and thus was most certainly not representative of the kingdom of the Creator God of Israel.