Yes, that's a really good point.
Ok, I've just given myself a task - see what I could do to speak up about disability next week.
Last week, I challenged supermarket access for disabled, challenging a stereotype about mobility problems. The manager was helpful and positive. He can't officially override what someone more senior has chosen to do, but he and his colleagues can take a practical, helpful approach and he says they will. I believe him based on staff behaviour.