There is a difference between being a good colleague and allowing a shakedown. 

In some workplaces, the fine line between normal and unreasonable expectations of coworker generosity is frequently trampled on. It is all well and good to expect somebody to demonstrate being a good team player, but it is not always fair to demand a significant amount of time, effort, or money without some form of payback to be had. The ideal culture of the workplace should be something that feels beneficial for everybody who is involved.

The issue with these overenthusiastic expectations for coworkers to contribute to various nonessential work matters is that not everybody is going to be on the same page about them, or want to be a part of it. This is not always a terrible thing, but it can leave those who opt out feeling like they are facing consequences for acting on their opinions. The reality is that for many of those in the working world, being competent at your job is not enough to make you a good colleague. You have to be a part of what happens outside of it, too, even if that appears to be unnecessary or unfair.