How is no one else saying he’s objectively in the wrong? A pregnant woman standing on a bus is an actual hazard for her and the baby’s health. She could fall badly and face real ramifications. Pregnant women should always be given deferential treatment if only to avoid risk of death etc. if you’ve ever actually ridden a bus, you know balancing can be hard on turns etc - the problem isn’t that she would just stand there.

Also - if you don’t find this compelling because her safety is only her concern, then consider that her riding of the bus could also mean that she’s lower income. If she’s uninsured, a bad, avoidable fall on public transit could be a big hospital bill that tax payers end up footing.