The idea that all religions lead to God is logically indefensible, since they contradict each other at the most basic tenets. Furthermore, the religions of this world do not even claim to serve one god who presides over humanity. Regardless of what belief system that one espouses, he will inevitably be making a truth claim. Intolerance of opposing views is what follows from faithful adherence to any given worldview. Consistency and coherence demand that one make an absolute truth claim. That is simply a part of being human.
Christianity is unique among the religions of this world in that its message of salvation is one of God's unmerited grace through faith (Ephesians 2:8-9). Others teach salvation to be merited in part on the basis of human efforts. Christianity is the only religion which posits a realistic view of our sinful nature. The Judeo-Christian worldview is unique in that its God desires to have a personal relationship with man. Truth is very much a real thing. Something can be either true or false. It cannot be both ways in the same way at the same time.
The gospel is available to all who call upon the name of the Lord. No one deserves to inherit the kingdom of God, since we have sinned against Him. Christianity is an inclusive religion in the sense that the atonement of Jesus Christ is applied to all who believe on Him for salvation. Christianity is exclusive in that it presents Christ as being the only way to obtaining fellowship with God.