No one ever answers this, but ill ask again anyway...
How far does this go?
Can I call myself king of England And axpect to be treated as such?
Can I be devoutly Muslim, but call myself a Hindu?
Can I call myself a vegetarian if my diet is 100% carnivorous?
At what point does "allowing" every precious snowflake call themselves whatever they want become ridiculous?
King of England isn't as black and white as you seem to think. Many people have tried to claim the title. When the Tudors took the throne, their claim was tenuous at best. After Richard III died, they launched what we might call a PR campaign today, claiming Richard III was a very bad king and they would do better. It worked. So you may want to hire a PR firm in your quest to be regent.
I'm not certain if Muhammed ever restricted his followers from calling themselves Hindus, but, the way things are now, I would think you could be beheaded for it. Certainly you could try it, but expect dire consequences. In the US there are enough people who claim to be Christian without any evidence of Christ's presence in their lives, to make this seem obvious.
I'm not sure why you would want to call yourself a vegetarian if you're actually a carnivore - not even an omnivore. You would be served inedible dinners by well meaning friends. But, yes, you, can call yourself anything you want as long as you're willing to suffer the consequences.
Snowflakes have no consciousness. You can label them at will. The Inuit languages have long be reputed to have many more words for snow than languages originating in milder climates. This has been disputed - apparently they have generally the same number of words for snow as in English, but many more options for combining those words for far more subtle descriptions of snow than in English.
So you don't have to call a snowflake whatever it would like to be called, as it's inanimate, but there might be more accurate things to call it than a snowflake, because some people pay more attention to snow and have a more subtle understanding of it.