> "Christianity is based on the life and teachings of Jesus"
> It may be possible for modern Christians to claim this while sounding reasonable (because it seems this way, listening to the words), but the statement falls apart when we try to verify.
Christianity is based on the life and teachings of Jesus, and the belief he's the messiah from the canonical gospels (Old Testament). The religion was founded to gather his followers.
So, yes, you can say Christianity is based on that.
> Specifically, I've met and had in depth discussions with many Christians (including priests and lay people) from different schools. None of them could tell me what the teaching of Jesus is. Some were able to tell me words that they had learned, like "love" or "truth" or "law", but upon my questions made through those terms (e.g. What is love?), no one among them could answer with substance.
Jesus preachings weren't in a philosophical level, so you'll never get an answer from a Christian about the nature of love ("What is love?"). For this you want Plato.
In his parables [1], though, he left messages about the importance of loving and forgiving, among others. These teachings just aren't synthesized.
[1] http://en.wikipedia.org/wiki/Parables_of_Jesus
> (...) but it's because he told people the truth about religions that he was killed by the religious people in those times.
He neither preached in favor or against religions, so it's untrue to say he was killed for that. Jesus was crucified for political reasons, for Rome couldn't let a gentile gather a following. That was standard practice during the Roman Empire, to publicly kill local/tribal leaders.
> That's how I know that education/propagation of Abrahamic texts is quite antithetical to the life activities of Jesus himself, and their inclusion in a religion precludes the coexistence of the true teaching of a saint such as Jesus.
The fact Abrahamism is incorporated is an historical accident - these were the gospels of the people who funded Christianity. For instance, the talion law from Exodus ("eye for an eye...") is later discussed by Jesus in a different perspective ("whosoever shall smite thee on thy right cheek, turn to him the other also").
So, yes, it can be conflicting for religions that postulate following whatever is written - or worse, the parts they want you to follow, since the gospels have been manipulated endlessly. But the fact they were part of the foundation of Christianity isn't necessarily bad, because it's part of their history.