Simply put, being a disciple of Jesus isn't about behavior modification. If that were the case, we are pretty hopeless, because I don't know anyone who is sinless. Yet, how often does our Catholic culture push behavior modification as the primary goal of our faith? Too often, at least in the way we structure our parishes. In fact, think about the culture of Catholicism at the local level.

When a visitor comes into your local parish, will they not only be told "hello" or "welcome", but will they meet someone who will introduce themselves and talk to them, invite them to coffee, and make them feel valued? Do we have an expectation that someone knows to be quiet (and pray) before Mass or turn and greet your neighbor? What about how small children are to behave at your parish (e.g., take them to the back if crying)? There are so many unwritten "rules" of our parishes, we rarely think about or even moreso, challenge.

I recently heard a story from a great Catholic family who moved to a new city. When they registered at their new parish, they received no phone call (or email, letter, etc) to welcome them. All they got were instructions on how to make donations. What a shame. The unwritten expectation is that the family is supposed to "behave" in a certain manner, from the start.

Think of this situation. How would your parish handle it if men wanted to join a Bible study or adult R.E. class at your parish? Probably no big deal, right? But, what if 2 of those men were living together, as a couple? Would they still be welcome? Probably not at most parishes. The looks, gossip, shunning, and more, would probably eventually drive them away, if the other barriers to relationship didn't first.

To be clear - I am not saying we are to accept their lifestyle as something good for them. What I am saying is we are supposed to love them, unconditionally. Love would compel us to reach out to them as a friend, not start with behavior modification, in order to "believe" correctly and then they are able to "belong".

Still, this is how we operate in most places in our Church. My position is that the model of Behave, then you can Believe, then you can Belong, is a failure. 
BEHAVE -> BELIEVE -> BELONG just doesn't work!

The better model is to think of how Jesus did things.
BELONG -> BELIEVE -> BEHAVE is how Jesus operated.

He entered into relationships with others, regardless of where they were, spiritually (or morally, socially, etc). He befriended tax collectors, prostitutes, and others. Once they felt a sense that they could "belong", Jesus then invited them to follow Him, to "believe". After they chose to believe, he would ask them to "behave" a certain manner, so they could live an abundant and fruitful life.

This is like any relationship. When I dated my wife, we built a sense of friendship first (belong). We decided that we wanted to be more, so we made a conscious decision to solidify that relationship (believe). Only after we fell in love, did we want to start to be better people for one another (behave).

A similar dynamic happened during my initial conversion in college. I had a group of friends, who loved me enough to be my friend, despite all my sins and problems (belong). They eventually invited me to a retreat where I had a conversion and decided to follow Jesus (believe). After that I started to change my life, because I fell in love with Jesus (behave).

Think of the parable of the sower and the seed.

The seed on the path, where the devil comes and takes it away - these are the ones who hear the word, but don't believe. These people never believe, behave, or belong.

The seed on the rocks, where it shoots up and then dies, because it has no root - this is the one who just wants the good feelings of Christianity, without the rules. These people may behave (for a short or long time), but never really believe in it or belong fully to it. Think of a cultural Catholic.

The seed that falls in the thorns, where it is choked by worldly concerns and desires - this is the one who wants it both ways, but in the end chooses the world, not Jesus. These people may belong (in some way), but they don't believe or behave. They never mature.

Then there is the good soil - which produces an abundant harvest. They belong, believe, and behave!

Start with allowing others to belong. They are our sisters and brothers we must love. But, there is so much more to Christianity, we aren't just a social club.

Then move to believe. This requires conversion, so we must be evangelists! We can't stop with mere belonging, because true love desires salvation and holiness for others. Still our faith isn't something we keep to ourselves or let stay stagnant, without changing us. So, we must have more.

Finally, we can challenge others to behave. We have to model it, move to intentional discipleship relationships, and real Christian community.

BELONG -> BELIEVE -> BEHAVE = the model of Jesus.

When we get this process reversed, it leads to problems like we are dealing with today. Get it right and we can "make disciples of all nations".