So-Called Gurus

Why so-called gurus with good and positive intention become a barrier for realizing the truth?
I have notice that there is thousands of spiritual teachers and so-called gurus, starts with a philosophical or theological idea, somehow gathered a group of followers and create an organization. The strange point of these so-called gurus is they fits in the mechanism of mind even their ideas are little bit deferent to each other.
The few real masters that this universe has produced have unique way and almost all of them, when they were alive somehow they were unfit to the mechanism of society mind.
Some of them were killed, crucified, poisoned and so on.
Are so-called gurus blind with their so-called ideas are able to recognize, if in front of them pass a Buddha?