Ans.01. Jesus' teaching, i.e. "truth will set you free", is NOT an allegorical statement and this concept is far older than Christian theology.
02. Like Christianity, Islam has many different branches and many different sects within those branches with many different imans putting their own spin on what Mohammed said. The Sufi branch of Islam holds that seeking truth is how man evolves into higher states of consciousness and frees himself from bondage to false illusions--very similar to the teachings of Gautama Buddha and Jesus.
01. "Truth will set you free" has many shades of meanings and in such issues there is flexibility and it is not a Dogma.
02. I know that Muslims got divided into sects and each one is giving importance to their own interpretations.
When humans try to understand scripture, there is bound to be some difference of opinions and some disagreements, but they have to be within limits and people should not make sects and each start arguing and condemning others.
03. Sufi teachings based on Quran and sayings and actions of prophet are laudable and no one is against them.
But when some one leaves straight path and starts giving more importance to their visions and their mystical experiences which go against direct teachings of Quran and ways of prophet, they have to be rejected.
Teachings of all past prophets have some basics in common.