I am not sure if anyone else feels this way but...A lot of people label themselves. I might seem like a hypocrite for the forums I've posted but I get allot of constructive ocriticism. Maybe not constructive because most people claim it is but in all reality they are putting you down. Constructive criticism is a good thing to have and it is 100% necessary. Thing is a lot of people say oh well this person who practices this magick is called this. Isnt it all magick? We harness and utilize the same energy just in different forms. And we label it. If you want to be a witch you can't practice this or that. you are you and you can practice what ever the fudge monkey you want. Stop letting people label you and tell you What is right and wrong. If you want rules go be a Christian or any other label. Stop slapping labels on peoples foreheads and telling them what they can practice and not. If you want to be a witch and practice high or ceremonial magick do it. You don't need to be some special magician to. You are who you are. You don't even need to label your self a witch to practice magick.
Good post, though I don't normally see people saying 'you're a necromancer, you cannot practice Reiki' or whatever. True, you should follow what you feel is right and what interests you. Sometimes labels can be a good things, but only when you choose said label. There really isn't a rule saying what you can or can't practice, besides The Wiccan Rede, but that's not universal, just for Wiccans, and even then some define 'harm' in different ways.
Now, I have seen people saying yes or no to certain studies for various reasons, primarily because they don't exist or are contradictory terms. Christian Wicca comes to mind. I have no problem if you choose to be a Christian Wiccan, but it is a contradiction so I see why people get upset. It's the old saying 'have your cake and eat it too' Wicca can be rather flexible, Christianity not so much. But if you're happy whatever.
Labeling is more psychological aspect. People always like to identify others and themselves in a crowd and by labeling they become part of some community or they show what position they take in that community, etc.
It is a form of communication.