That Jesus is the Gate and all the others are up to no good. This implies that anyone who is not Jesus or pointing exclusively to Jesus is trying to lead people astray, rob them of their worth, and ultimately lead them to death and destruction. That seems... severe. So Jesus, we'd like to know, “Why so serious?!”
We have a rough time associating with in our daily lives. Being "saved" implies that we needed saving, but until some of us hit a crisis in life we don't feel we need to be saved at all. Rather, we feel pretty powerful; kings of our own castles feeling like we are running the show like MTV Cribs or something... if you haven't seen it don't worry you aren't missing much, in heaven will be the best crib of all.
A Jewish guy, the son of a woman who was allegedly a virgin, born into family of charismatic zealots, decided to base the entirety of his life on earth on a single reality: everything exists because of Him. Not many people have said things like that. Not many people have gone into as much detail or even died to prove it. And, history suggests, not very many people chose to die the way that he did either.