Saying it doesn't make it so
Calling a church a church, or declaring a church not to be a church doesn't make it so. As form follows function, so the reality of what constitutes a body of the Lord's people follows the key question of whether or not that body is made up of the Lord's people, and if they meet together for the purpose of edifying one another and praising God. If so, it is a church, or ekklesia. It is a congregation of believers. It may or may not be a very healthy congregation, and it may have a sectarian name on the building that some wouldn't be comfortable with. It may not even be very effective in accomplishing what God intended the church to accomplish. But it is a congregation of believers nonetheless. As Alexander Campbell once wrote, "he that lives in the wilderness still lives."
My point is that the organizational shells of denominations as embodied in their legal structures or traditional practices neither make them a church nor keep them from being a church, in and of themselves. Of course, some organizational practices have been more effective and some have been less effective at accomplishing the task of unifying, edifying, and building up the local body of believers in any given location. Some in these organizations have done things that run completely adverse to the goal of promoting godly lifestyles, such as appointing openly sinful and blasphemous individuals into leadership positions. In those cases, sinners are sinning while some Christians are voting for and applauding it. Moral depravity is not immune from rebuke under the guise of Christian unity.
But immoral individuals aside, the organizational scheme itself is neither a church nor an anti-church. It is plain vanilla, so to speak. It is merely a context in which people agree to meet together. It is a body of rules and regulations of men that are simultaneously as authoritative and meaningless in the eyes of God as the Boy Scout Manual. True, these rules and regulations are bad to the extent that Christians enforce them as the will of God and use them to divide God's people, but they are harmless to the extent that those who meet in organizations that have adopted the rules and regulations don't necessarily adhere to them or use them divisively. We have to separate the organization from the congregant.
This means that true believers, many of them, in fact, can and do exist within sectarian pastures (which have grown to include the Church of Christ), and that their allegience may be unintentially divided between a human superstructure and the Foundation of our faith. But our job as fellow brothers and sisters in Christ is to edify them in love and to be edified by them whereever possible. And if we think the edification only needs to go one way, then we've forgotten what the term "mutual edification" really means. In fact, we've forgotten the entire first half of the only verse using that phrase.