As a traditional style of Martial Arts we can take pride in how close our techniques are to those of our O-Sensei.
Why do we bow, why do we have to help keep the dojo clean, why can't we wear what we want to class?
Without respect we would quickly lose sight of where our Karate came from.
By bowing when we enter the Dojo we are respecting the space that allows us to perfect our Karate. By calling our instructor Sensei/Sempai we are showing respect for the path that brought them to being our teacher. By bowing to our partners we are thanking them for helping us practice. Our "bow-in" at beginning or end of class is showing respect to Sensei's no longer with us, to our hierarchy of instructors and the sensei/sempai teaching the class. Think of it as the respect we show our families and elders; you don't get in or out of grandmas house without a hug, and you don't call grandpa by his first name. We are not worshiping them - we are respecting them; who they are, what they stand for, what they do for us and because without them we simply would not be.
"Rei" is respect for the history of Goju Ryu Karatedo, and the culture whose practices we follow in the goal of keeping traditional Goju Ryu Karatedo alive for future generations.
If we don't respect the history and culture of the art we practice we are simply misappropriating it.