"the false teachings had to be weeded out."
But who is to determine whether a spiritual teaching can be labeled "true" or "false"? The WT calls all religions except their own "false". To me, the term "false religion" is like calling a painting you don't like "incorrect art". Art is subjective and can't be labeled "correct" or "incorrect". The terms simply don't apply. If faith could be labeled "true" or "false" it wouldn't be called "faith" - it would be called "science".