This page in a nutshell: Any material added to Wikipedia must have been published previously by a reliable source. Editors may not add content solely because they believe it is true, nor delete content they believe to be untrue, unless they have verified beforehand with a reliable source.

Verifiability is as important as truth.

But reliable sources are biased!

From WP:BIASED (Wikipedia:Reliable sources#Biased or opinionated sources).

Wikipedia articles are required to present a neutral point of view. However, reliable sources are not required to be neutral, unbiased, or objective. Sometimes non-neutral sources are the best possible sources for supporting information about the different viewpoints held on a subject.

(Bolding mine)

But reliable sources are chosen by biased contributors!

OP attached to their comic repost RSP columns.

Deutsche Welle: Reliability was never discussed in an RFC. Anyone complaining here of bias does not acknowledge their possibility (if they are not banned) of making an RFC on it.
Voice of America: Discussed on RSN a few times. The last one is pretty interesting: Here
Xinhua: Discussed here. ITT: It's quite old, but Xinhua is very controversial.
Telesur: Discussed here around seven years ago. Quite conclusive, I would say.