You're absolutely right, it's no real help whatsoever. But there's also no other actual guide beyond just having to learn the hard way to discern people's true intentions, which is difficult and exhausting while astrology appears so simple and easy. This is not in any way a justification, just my explanation of why it's so pervasive and attractive, and why the state of the world cultivates pseudoscientific beliefs in general - of which astrology is merely among the most socially acceptable to display, and therefore has the largest reach.

I definitely think its use in making life decisions is actively harmful, but it's hard to pull people away from what may be their strongest social connections. In this way it's just like any other real religion, which as Marxists we obviously oppose, but we also have to understand that these beliefs, and the psychological need for these beliefs, arise from social conditions of alienation. So until we're in a position to change social conditions, just attacking the belief system and the people who believe in it won't achieve results and will just push people away. Especially when so often, the people holding these beliefs will come from among the more marginalized intersections - probably not a coincidence, as if you're a member of a group who has much more control over their life why would you need to look for guidance in the stars?

When the time comes, I'm sure there will have to be some kind of cultural revolution to sweep out every kind of pseudoscience, from astrology to crystal healing to reiki to everything else, but until then all we can do is tolerate these beliefs in our allies, push against them in our actual comrades and make sure they're never used to make the really important organizational decisions.