Please clarify why A Wouldn't be Wrong (wording)

In the stimulus, it says that "virtually every" development proposal brought before the council in recent years indicates that their expressed concern for the environment... but then the answer says: "Not every" development proposal opposed in recent years by these so-called environmentalists was opposed because they believed it to pose a threat to the environment. I don't understand what these two statements are saying and why A isn't just repeating what the stimulus says.