And if they didn't know it, why not just watch the other movies where these things happened? Or read the stacks of comics where they happened. Or watch the animated and live action shows where they happened. Or get on Wikipedia and read the first paragraph of the character's page.
It seems like audiences today are starving for something new, but time and time again, studios hit that "reset button" and suddenly we're back in the classroom with wimpy Peter Parker, looking at our watches, waiting for him to get bitten by the friggin' spider already.