There's a lot of people out there who don't like organized religion. I suppose maybe they're okay with unorganized religion; it's just the organized kind they don't like.
That raises two questions for me. First, what is organized religion, and second, why do people have a problem with it? Presumably, if a person says they don't like something, they know what it is they don't like. It wouldn't make sense for somebody to say they don't like organized religion if they don't even know what they mean by "organized religion." So these questions are best answered by those people, and not me.
I'm going to offer some speculations, though. When people say "organized religion," I take them to mean the same thing as institutionalized religion. That is, a religion that has some structure involving different roles for different people, a government or heirarchy, etc. The Catholic Church is a good example. They've got a Pope, cardinals, bishops, priests, and ordinary folks. There are rules for how they run their organization.
When people say they are against organized religion, they could mean one of two things. Either they don't personally prefer to join one, or they don't want there to be any. If it's the first, I suppose there's not much you can say to a person who doesn't like organized religion anymore than there's anything you can say to somebody who doesn't like broccoli. It's just a matter of personal preference.
If it's the second, then that raises another question: What's wrong with organized religion that people don't want there to be any? I think there are two reasons. First, because they don't like authority, and second, because of the evil organized religions are capable of.
There are two senses in which a religious heirarchy can have authority. The first is just administrative. They tell you what to do. Some people don't like to be told what to do. The second is more religious. They tell you what to believe. People object to being told what to believe more than they object to being told what to do. If they don't accept that some leader is in any better position than them to know truths, then they can't accept anything the leader says merely on their authority. They must accept it because there is good evidence to think it's true. But if they must accept it on the authority of the leader, then this seems to require them to give up the use of their brain in order to submit to the authority of the leader.
An organization can be more effective than an individual, because an organization can divide up responsibilities, so that people can pool their abilities together for a common purpose. In the past, that has often amounted to some evils, such as the inquisition. These kinds of evils scare people away from organized religion.
My only response is that evil isn't a necessary byproduct of organized religion. The common purpose can be good just as well as evil. So I personally would not object to organized religion just because it's organized. If anything, I would only object to it's purpose if that purpose were evil. Many religious organizations pool their resources for a common goal which is good. For example, my own church likes to build homes for poor people in other countries, and it takes a team effort. There are those who finance it, those who do the planning, those who supervise, and those who do the manual labor.
Christians organized themselves into churches, not just for the benefit of the poor, but for the mutual benefit of each other. As Paul points out in Romans 12, 1 Corinthians 12 and Ephesians 4, the purpose of the church is to build each other up in the faith and knowledge of Jesus Christ, and we are all gifted in different ways so that we're able to contribute. We need each other.