So this year, they added Facebook also: https://fosdem.org/2020/about/sponsors/
FOSDEM is about open source, not freedom.
Why is this a problem? Read this: https://ar.al/2019/01/11/i-was-wrong-about-google-and-facebook-theres-nothing-wrong-with-them-so-say-we-all/
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko