Why do Christians distort, exaggerate and at times seem to lie about the Jehovah Witnesses?

Christians on the whole do not lie about Jehovah's witnesses. I don't think that a true Christian would do such a thing. You can never say that a whole group of people do any particular deed or work. We are all different. There are false Christians as well as false teachers, false prophets & false religions. It is up to the individual to spend time with God & get to know Him & be able to have God lead them to the truth & guard them against what is false. God will do this for you.