Wicca is not a belief, it is a priesthood huge difference, if someone was to believe in something then yes no one should be able to tell them otherwise, but if someone claims to be in a religion or priesthood which they do not belong then people can very fairly and rightly point out that they are not.
This, and the text that followed, was quite exacting and dogmatic. It listed all the things that a “true” Wiccan practitioner had to do. I don't claim to be Wiccan, so I can't speak to the particulars of the beliefs expressed. My path is shamanic, and I can draw correlations to it. In the shamanic path there are very few "Shamans" with a capital "S". Shamans are recognized by their tribe/group/culture, and those who take on the mantle themselves are suspect. Those people who embrace this path, and are not recognized as being Shamans, can instead say that they are on the shamanic path. Specific traditions have specific beliefs, and the quote above was the start of a list of beliefs for that priesthood of Wicca. Different groups have different measures of what a shaman does and does not do. When a person meets the requirements, the group says, "You are a Shaman". This does not mean that the person is qualified to be a shaman for the tribe next door.
My second thought is that the listing of a priesthood eligibility list is as confusing as it is helpful. There are many people who cannot be members of a coven structure, and thus be formally recognized to be priests. They are left looking at these lists and wondering, "why is that a requirement?" It is my personal belief that a dogmatic requirement laid out, without an explanation of why it is done, is a barrier to those coming into that belief. I live in an area that is very coven poor. Those that exist are closed and hidden. Newbies/beginners have no official path to the Wiccan priesthood, and those that do exist are of poor quality (IMHO). What are they to do? Is Wicca going to die in the southeast because to be Wiccan one has to follow rules A through Z, but there is nobody to teach these rules, and then officiate the recogniation of the resulting priests (and priestesses)?