Jehovahs Witnesses are not Christian any more Scientologists are. The Scientology cult is the product of L. Ron Hubbard's imagination, a cheesy science fiction/fantasy writer.
Jehovah's Witnesses are likewise a cult conceived by Charles Taze Russell, who have from the beginning claimed that mainstream Christianity are heretics based on their own flawed interpretation and have done their best to distance themselves from the Church, which is Christiannity as taught by Christ himself, up to and including their insistence on claiming the Jesus was actually hung on a "torture stake" as opposed to a "T" or a cross, as propagated by the Roman Catholic Church.
As you can see, JWs will claim that everybody else is the "non-Christian", especially the RCC or any mainstream Christian believer. The organization was eventually taken over by Franklin Rutherford, who modeled their recruitment methods after a pyramid scheme. They claim to do charitable work but will not disclose how their charitable donations are spent. They also believe in barbaric practices such as shunning relatives for minor offenses, such as receiving blood transfusions, offering flimsy scriptural support as their rationale.
Their dogmatics are entirely non-Christian, starting with their claim that Jesus was actually Michael the Archangel. They're not Christian's in name only, they are not Christians at all.
Finally, they have dishonestly rewritten parts of the Bible in support of their flawed theology, a demonstrably non-Biblical practice.