Don’t you realize that all of you together are the temple of God and that the Spirit of God lives in you? God will destroy anyone who destroys this temple. For God’s temple is holy, and you are that temple. (1 Corinthians 3:16–17).
When you hear someone telling you all the bad things about a particular church (usually to promote their own church) you should give them the warning of this verse. They are trying to destroy God's temple and that brings negative consequences from the Lord.
God's people are called to recognize that the differences in churches who are preaching the gospel are usually more about preference than substance. To attack each other is like having the army attack the marines! WE ARE ON THE SAME SIDE!
Would it be nice if we all worked together? It would. It would require seeing beyond building our own "kingdoms" and truly focusing on building His. It would require grace and understanding rather than judgment and condemnation.
The Holy Spirit wants to work in and through His church. For that to happen we have to focus on the enemy rather than our allies! Jesus' prayer was simple: "May they be one father, as we are one." So may it be.