Do they? Nobody buying this stock thinks Hertz is going to recover.
They think "I'm bored and buying this worthless stock is risky and fun".
That is valuable to some people, and hence why the stock price is up.
Hertz selling more shares to try to save the company is pretty dumb, because that is not what it share holders want.
Hertz new share holders want to see the company and stock burn as much people as possible in the most spectacular way possible. That's what Hertz has become.