Because some of us take an interest in what is being done to maintain, operate and - dare I say it - improve the infrastructure. Even if we can't use it, being involved in our public services helps our communities function better. Involving people in timetabling trains or buses will usually reveal something which can be improved for real-world use. Involving local businesses or charities in the commercial and public spaces of stations often helps them work better. Involving people in the explanations of how the service is actually running, in real time, may shock, concern or worry them if done wrong; but framed correctly (and I am not claiming that is easy!), it will build a picture of how seriously the frontline staff generally take what happens on the ground, let them query it, and let them understand that a delay may occur at the cost of their safety. Understanding that positive actions have to take place, even at the cost of punctuality, may sometimes fall on deaf ears. But for the majority of people, it will at least let them know that the specifics count, that the railway cares about accurately working out how to get round a problem, and that it can be discussed if necessary.
My own interest in the railways, indeed my career, came about largely from trying to understand more and more about how the railway operates, how it should & could operate, and what I can realistically do to help its passengers on their way. I do appreciate that some people have no interest whatsoever in how it all works, and more to the point I appreciate that very few people have any interest in standing at the end of a platform all day with a little notebook, or poring over Quail until 2am. But from what I can tell from discussing things with rather large numbers of people - thousands of passengers over the last few years - almost all prefer discussing how the railway works, as well as seeing it be more transparent, explaining the system and trying to make sense of media report or political spin versus reality. The railway is moaned about because the slightest thing which goes wrong can impact so much. Only by explaining how it works, and how it sometimes doesn't, can people be brought on side and it is the only way to start to get them to generate constructive (positive or negative) feedback to get public money and business strategies to the right places in the very long run.
In other words, passengers can and do actually care, if you discuss it constructively. Not all will. But if you hide things or don't explain the system, they will only care about demolishing it for you.
