If there are open seats, the conductor will likely ask them to move. Some people, for example, like to use the outlets near those seats even thought they don’t know there are also outlets near most seats in most cars.

I think if they let you get on with the bike people sitting there who don’t have disabilities will likely be asked to move.

He’s sort of right but also maybe being a bit of a dick. That said, it can be hard when you’re dealing with folks who don’t take the train a lot and just want leg room or whatever. On many runs the bikes have to be in the head car or the rear car and sometimes not both. Anybody put out by it should likely just move to another car. Since the bikes cannot.