Wait, are you up in arms because you are are frugal or because someone was giving?
I am cool with giving back, but I am not going to do it for the "common good", I am going to do it because Jesus taught us to. But specifically, Jesus has instructed us to care for those who's support system has been taken away from them (ie, widows and orphans). God never told us to care for people who have plenty of recources and to do so at random. Instead we are to help the widow who's husband (who had resources to support his family) has died and the money in savings has dried up. Or the children who's parents died and now they are facing homelessness and starvation as a result.
I don't like to donate money to organizations, or "causes" at random, I like to help a specific person or a specific group of people.