You keep repeating the "by volunteer" line over and over again. They pay people to head the development of the wiki software, including paying developers and managing the project.

The same goes for them managing the huge portfolio of Wikipedia sites.

They run one of the most visited and iconic websites online today in a way that is totally unique at that level. If you want to run a smear campaign against them, in here of all places, you need to do better than "it's a community driven OSS site, and they accept donations!"