The so-called zealots are often the folks who have been around long enough to understand that Evernote has historically and consistently been uninterested in providing nested notebooks (this particular thread is a prime example). Pointing that out, and advocating for the use of tags, and offering examples like GMail to show that hierarchical containers aren't necessary features in a product like Evernote isn't attacking anyone; it's giving some context to the conversation. I feel like I understand the use case pretty well (and I'm sure that Evernote does as well), and while I don't need nested notebooks, I understand why some folks believe that they do, or maybe actually do. Sometimes it does indeed come down to the fact that they don't understand tags, and sometimes some tips can help that.
Regardless, only Evernote can make the decision to implement nested notebooks, and since they haven't, we users have the power to choose whatever competing product that suits our needs / budget / aesthetics is available, while those that want them in Evernote can continue advocating for them. If that's done respectfully and reasonably, then that's welcome to the conversation as well. Some of it is not, however, and I think that that's when most conflicts occur. *shrug* 'Twas ever thus, on the Internet.