Why do people have beliefs as Christians that contradict other Scriptures yet believe they are right?

With God all things are possible.

Diabolical disorientation.

Much of scripture was "inspired by God" in the specific sense that a writer found something in earlier-written scripture that needed refinement, correction, or outright contradiction. The entire Bible is not so much a divine manifesto as a collection of major contributions to over a thousand years of arguments. 

Perhaps the best compact illustration of this is in the Sermon on the Mount. In Matthew 5, Jesus declares (verse 17) he has not come to abolish the Law and the Prophets (Torah and Nevi'im, two main components of Hebrew scripture) but to fulfill them. He follows this immediately with a list of scriptural references, in each case offering his own, changed, version intended to "fulfill" it. 

You are the most Bible-contradicting Christian I know.

Even moreso than Jehovah's Witnesses.

Ask Norine about that.

"Many believers admit that nothing could change their mind about their religious beliefs, which means they are no longer seekers of truth and have become, in essence, mindless religious robots. Religion consistently and effectively discourages introspection and inquiry. That isn't by accident."-- Bob Peters

I wish I had an example of a belief that I or other Christians might commonly hold that contradicts scripture that is canon to the Christian religion. I say this because I honestly have no clue what you are referring to and therefore no real answer to your question. 

Every religious cult, dogma, beliefs and practice is their own. Why? because people cannot agree on anything, religion, politics are the most common of disagreements.

Good question.  I'm assuming you're presenting your own time on this forum as an example of what you ponder.

And being that offered no examples, no citations nothing but a wild unsupported assertions.....you get the first boop of the day

*edit what the bible says is that there is one baptism FOR THE FORGIVENESS OF SIN. The baptism of the Holy Spirit is for the power to minister NOT to save