That seems a rather strange argument to make considering that the vast vast majority of web services are not Free Software. Do people really feel like they are making the world better by using Free Software to make all those Non-Free web services?
- I'm not giving money or support to proprietary vendors. I am, however, contributing by filing bugs and maybe hanging out on the mailing list for the open source system.
OR
- I am contributing money and maybe code to the open source vendor, in addition to above.
OR
- Even a comment about how your service is built on F/OSS system can significantly improve its standing in the world, if your service is well known.
Therefore, even though I have a proprietary licensed piece of software (due to lack of visible business model for xyz), I can provide significant help to the tools backing me up.