In your example, by ignoring the "working class" and their issues, you implicitly leave the existing (both good and bad) structures in place.
To the second (things change anyways), structures and the world reform due to pressure from individuals within and without. So, yes, perhaps you can hope the system changes without your input (and honestly due to human limitations you really shouldn't have involvement in every issue) but my point is ignoring the issue isn't purely neutral. You are instead offloading the responsibility of change to others. So my point is to point out how being "passive" is actually an "active" choice with consequences.
Interestingly, by cycling, many would argue you made an actual statement by your lifestyle that influenced others on a topic. This is why people use the term "everything is political." Your actions, as you noted, spoke louder than any verbal advocacy and changed people's lives. This leads to a similar statement, "be the change you wish to see." Because verbal advocacy is often easy and simple and valued much less persuasively than actions and lifestyle.
Does that make sense to you? Or perhaps I'm misunderstanding your positions? These are great questions and good examples!