Coming from the middle of the United States (OKC, OK) I have encountered the following Buddhist groups: Vietnamese (Mahayana), Korean (Mahayana), Thai (Theravada), Chinese (Mahayana), and Californian (Zen). After spending time at the Kopan monastery in Kathmandu I have also experienced Tibetan and, of course, the Theravadan people here. Every one of these groups have differences. Some rather vast and many rather surprising.
So my first response would be - by whose standard are you evaluating their interpretations to be wrong?
To call themselves Buddhists one asks ...
Do they seek refuge in the jewel?
Do they follow the 5 precepts?
After that it's a matter of school and lineage. I have noticed much more of a dao influence in the Chinese Mahayana group compared to the Vietnamese (who seem much more pedantic). And the Korean group has prescriptions of an origin I still dont know. The Zen group seemed much more Hindu in nature (even mixing in Yoga ideas of shedding karma) and the Tibetan group from Kathmandu was much more mystical than purely secular.
I mention all this because there is a wide variance in views and all maintain some form of justification based on canon. I wouldnt rule any group out as errant until I had done my own homework beforehand. I studied the Upanishads, the Dhammapada, and the Bhagavad Gita before deciding which path I would follow and my determining factors were:
- my path must swallow all others in its' embrace, and
- my path would align with both the physical world as well as the spiritual.
That first factor requires a little explanation. After such an exhaustive search (50 years) for spiritual guidance I finally figured out that if a set of beliefs excludes any group of people then it is incomplete. Usually incomplete means it suffers from inaccuracies and bias. So any ultimate explanation should encompass everyone. It should be a universal truth to all ... swallowing up all other beliefs.
The second factor comes from my practical education and background. We ARE talking about the very nature of the Universe and I dont believe in magic. I do believe in science and physics and quantum mechanics and biology. I will certainly allow for discoveries we have yet to make (black box principle), but my path will be supported by known science and be furthered by it.
These are, of course, MY factors. You will have your own. Based on your background. Seek refuge first through learning about the Buddha. After you learn then find the path that suits you and a group of people who help you in it. Be up front about your search and the earnest questions you ask will be greeted with a smile by the right-minded. Not conflict.
I hope any single word of this was helpful. I understand this journey and wish you the best of results! Namaste my friend.