Huh, that’s so, it was there last January. It used to follow this paragraph (still there today anyway), which contains a similar criticism with citation:

It is widely used and has sometimes been criticised for its methodology.[4] Scientific studies[5] using its ratings note that ratings from Media Bias/Fact Check show high agreement with an independent fact checking dataset from 2017,[6] with NewsGuard[7] and with BuzzFeed journalists.

So if those are considered fact-based, there’s no need to delve further.

However, Wikipedia editors consider Media Bias/Fact Check as “generally unreliable”, recommending against its use for what some see as breaking Wikipedia’s neutral point of view.

source: https://en.wikipedia.org/wiki/Media_Bias/Fact_Check