If you give an infant solid food, it will wreak havoc on the poor baby’s digestive system. If you attempt to help a non-believer see how they might potentially be out of step with the life God had planned for them before they have even come to know and accept Jesus, it wreaks havoc as well.
As marketplace missionaries one of the most critical things we need to be effective reaching others of the Kingdom is God is having our own feet on solid ground when it comes to what Jesus actually taught. If we are off chasing false images of Christ given to us by these conmen that Paul describes, then the Jesus we are introducing others to will be not be Jesus at all.
It is not about what we are “allowed to do now” because of our new found faith. As a Christian our chief mission in life is to share the good news and help others come to saving faith in Jesus as well. To this end Paul challenges us to not put stumbling blocks in front of others. He challenges us to stop thinking about ourselves so much when it comes to these issues and rather to ask ourselves whether our actions are going to act as a catalyst to bring someone to faith or potentially push them away.