Long time ago I used to think the way you described: that technical analysis is BS.

But then I gradually understood this: in most cases the market behaves the way people think it will behave. This is just an inherent feature of a market: it creates its own future.

So even if what people believe in is BS, if enough of them share this belief when they watch the chart, this BS will materialize and it might turn out it was not BS after all.

Thus on the rational level your are right. In reality however, you are totally wrong.