I'm sure you, personally, could treat it that way as you haven't studied astrology and don't care about it. It's doubtful it works that way for those who use it heavily. Saying this is akin to saying you could assign different meanings to words of the English language and it wouldn't matter, and that it's all just a game. For people who speak English, a particular configuration of letters in some particular order carries a specific meaning that serves various functions. It's not as flippant as you make it sound.
For many people, spellcraft is personally empowering. It is a practice that empowers people, builds self-esteem, and helps people take charge of their lives. It doesn't sound like you've considered any of this in your assessment of the practices. As remarked earlier, it sounds like you fixate solely on questions of whether or not this stuff is "factual" or "real" when that isn't necessarily the point and does not govern the value of these practices. Again, these things are like arts. Look at what it does in people's lives. Look at the function and role it serves. It's a fantastic goal-setting tool that helps people get things done in their lives. Who bloody cares if the "woo" interpretations of it are "real" or not? The "woo" is not needed to practice, or for the practices to be effective and functional.
The thing is that words are constantly being created and reassigned meaning. Words themselves mean different things in different languages. If a word is no longer useful, or its meaning needs to be changed, they meaning changes. Language is driven by utility. English from Chaucer's time is very different from modern English. The English in Beowulf is incomprehensible to modern English speakers. The word "gay" used to be happy of sprightly. Now it almost exclusively means "homosexual". And words in English are not universal. If were to be a German speaker, the vast majority of English words would have no meaning at all. Some would even have a different meaning. The word "gift" means "poison" in German. If I created a code where the word "bottle" meant "elephant" then "bottle" would be "elephant". They is no scientific or universal attachment of concepts to words.
So if Astrology is an science, the meanings attached to celestial movements should be based on evidence. So long as there were no substantial evidence to alter these meanings, the meaning should stay static. If there were evidence to show that Aries were y rather than x, then ti should be presented in a peer reviewed journal and if there ever enough substantiated evidence to change the meaning of Aries from y to x, then the general consensus within Astrology could change.
However, if it is an art and a thinking tool, then the meanings attached to celestial phenomena cannot be substantiated, so there is no reason why their meanings can't be mixed up at will. It's like if I played a card game and decided the king was the most powerful card and then played a different card game and decided the Ace was the most powerful. I could reassign meaning at will because the purpose is to stimulate thought. So, if Astrology is an art, it has no more meaning than a card game, because the elements don't have any inherent meaning.
Spellcraft is fine as a goalsetting device and a psychological tool. But there is a difference between saying spells are a useful psychological tool and saying that spells use "energy" and "magic" from another dimensions to change physical conditions.
So, there is no supernatural or divine or scientific element at all. It's just people saying useful psychological tricks on themselves. That's fine, but if that's what it is, that's what we should call it. Many people who practice magic think they are summoning extra-dimensional "energy", not just mentally psyching themselves to do something.