He worked at the place the shots were fired from. He owned a rifle. He took it to work that day and used it. His rifle fired the bullets. All of the points you make are open to debate. For example, when his wife Marina was questioned, she was unable to identify the rifle as Oswald's. She later changed her testimony in this, as in many other matters.
There's more evidence that Oswald was not the shooter, than evidence that he was.