Elihu/Elijah
Your evaluation is correct. Not all that we learned as Jehovah's Witnesses is automatically incorrect. In fact, I believe that some of the teachings are still valid. Sadly, many who were once JWs have equated the organization with God. So, when they abandon the Watchtower they also abandon the Bible and God.
The teachings of Christ remain the same. The incessant discussions about doctrines often blur the simplicity of the original "good news" that was proclaimed by Jesus and his disciples. But in the long run, we are judged by our conduct toward others. ("Deeds" not doctrine.) Christians can have genuine disagreements as to the meaning about Bible passages...yet remain united in Christ. It is only when we judge other believers that we overstep.
Like you, I believe that the pagan origins of the holidays such as Christmas prevent me from celebrating. But if fellow Christians decide to participate it will be between them and God. However, I do believe that Christians have the right to express their views however unpolular they may be.