These are all valid points, but they are logically equivalent to saying "I don't understand why anyone pays $12 for a Ke$ha album".
You may not agree on the worth of the album or of the shares, and nobody is forcing you to buy either one. That some people do consider it a good price is enough to result in a market price for both, on the basis of which many decisions are made.
Well, no, it's like saying "I don't understand why anyone pays $12,000 for a Ke$ha album." If the price was broadly reasonable, there would be no argument. But if the price gets outlandish, then someone needs to call B.S.
And yes, this happens now and then for ordinary, exchange-traded companies. Usually, it results in the exchange suspending trading for the company for a bit. Sometimes, it requires someone to call B.S. In an ordinary, regulated market, one or the other of those actions restores sense, gets the price back somewhere within shouting distance of reasonable.
You may not agree on the worth of the album or of the shares, and nobody is forcing you to buy either one. That some people do consider it a good price is enough to result in a market price for both, on the basis of which many decisions are made.