Astrology is bigotry
Astrology is bigotry is an argument which posits astrological claims are bigoted if the claim prescribes behavior to people based on when they're born. Although most people who become fascinated with astrology first see it as a fanciful and helpful way of understanding other people, they often fail to realize that they are becoming prejudiced, and often bigoted because of their supernatural beliefs.
Consider the statement, "I hate Asian people because they're so irresponsible." Unless you're already bigoted against Asian people, you would immediately recognize this as a racist statement because irresponsibility has nothing to do with being Asian. Or, consider the statement, "I would never date a Jew, they're not loyal." Again, there is nothing about Judaism which makes someone disloyal, and, unless you already are prejudiced against Jews, you would see this statement as religiously bigoted. Now consider a type of statement frequently uttered by people who believe in astrology, "I would never hire a Scorpio, they're so dishonest!" Of course, what the statement is really saying is, "People born between October 23 and November 22 are dishonest." When stated like that, the bigotry becomes plainly visible.
Depending on the form of astrology you believe in, you might see Scorpios as actually being dishonest so you may not see how such a statement is bigoted, but