Well, about the messengers... was Buddha, Krishna, Moses, Abraham and even Muhammad tortured or stoned? But what does that have to do with Baha'is presenting their message in a way that offends people in other religions? By telling Hindus that they have misinterpreted their Scriptures about reincarnation... or that reincarnation was not in the original teachings of some unknown manifestation but was added in and is only a tradition of men, that is not going to go over very well.
But if you want to alienate people and push them away and show how your religion is superior to theirs, then fine. But, that's not what Baha'is are about. They are supposed to be bringing peace and oneness to the world... and show how all religions have all come from the same source. Or, do Baha'is really believe that religions aren't one? That all of them are corrupt and filled with man made ideas and concepts about God and the spiritual world? Then fine, tell how wrong they are. How far off the true path they've gotten. I don't know, so I like listening to what they believe in... and don't necessarily believe they are wrong. I understand that you do, because your prophet said so.
We believe what Baha’u’llah has told us but others are free to reject that. We put forth our arguments and others put forward theirs. No one is superior it’s just the sharing of differing views that’s all. And we are entitled to our beliefs just like everyone else is entitled to theirs.