The post isn’t asking our opinions of TA but rather for those that use TA to provide feedback. There’s obviously a market and this provides a product for that market similar to creating an app for astrologers.

The thing that makes technical analysis work is that other people are also using it. If a bunch of people/machines that make trade decisions see that a stock has some resistance at 115, because it's bounced off it several times before, they are more likely to anticipate that happening again and act accordingly. Since everyone does that, the predicted action happens. Then eventually there are other things that happen that drive it past that point, and people move on to the next set of signals.

If enough people believe it's true, it becomes true.

I don't use it currently, but I dabbled with it when I was younger (not as the only thing I looked at).

Dumb people are the best customers.

The big difference as others pointed out if that regardless of how many people believe in astrology, nature will do whatever it wants.

Financial markets, to a certain extent, can be manipulated by people. If enough of them believe that when the face of Jesus appears in the chart they need to sell, the price will go down.