When you open the door of your spaceship, the oxygen disappears from the ship.
So if I put a very very long tube from the Earth to space, would all the oxygen from the Earth automatically aspire into space?
And then no one can breathe anymore so everyone dies.
No. The Earth's atmosphere is held in place entirely by the Earth's gravity. There is no barrier at the top of the atmosphere keeping it from escaping. Running a straw from the ground to deep space would not change the gravitational force holding the air molecules down; it would, in fact, change nothing.
