Agree! This is a Christian belief - no human is perfect, so how can we have absolute truth. I think the problem is that human (includes some Christians) like to argue who has the highest truth, and in our corrupted way the argument leads to separation, hatred, persecution, and even war. But if we read Bible we should see that really God's command to us is to love!
No need to deny the fact - there are many Christian groups, big or small, around 10s of thousands. And there are always arguments about which group has the real, highest truth from God. Usually those in the leadership roles are involved in these quarrels. But many more brothers and sisters in various groups are simply following God. They do not follow the group's dogma, and try very hard to follow only God's teachings.