"... the white man was willing to stand and told the bus driver that he had no problems doing so."
Under the Montgomery city ordinance, the standing white man was *required* to take the seat that Parks was asked to vacate, when ordered to do so by the bus driver. This same ordinance also *required* the bus driver to demand that Parks vacate her seat. So, the racist ordinance had the potential to make the white passenger a criminal, for a simple act of courtesy to a (black) woman *or* to make the bus driver a criminal for not making Parks move and the white passenger take her seat.
If you ever want to have some fun, read both Thomas Sowell (articles and some speeches on the same topic) about who the first folks were to fight against the segregations laws, how they were imposed and how the political campaigns in favor on them were slanted.
Almost every single lesson of it applies today and all the same tactics are used across the board today on various policies.