They can, but they don't necessarily need to be.  If we accept that Jesus was a devout Jew of 1st century Palestine Who came to us because He loves us and desired to teach us The Way, we can also accept the fact that once He had absented Himself from this earth His followers would put a mechanism in place to contain what He taught.  These followers, being only human, as He was not, were bound by the cultural and political constructs of their time.  They organized, canonized, and demonized based on their knowledge and perceptions.  True, they were (and are) guided by the Holy Spirit, but Her guidance does not preclude any error, only material error. 
The structure of the institutional church, and all its doctrines, rituals, and rules are subject to change, modification, or suppression based on enhanced knowledge and wisdom.  The eternal truths, the church's dogmas (that is, Creedal statements) are unchanging but even they can be more fully understood and believed by His followers.