They’re saying the parts mbfc uses other data from is fine, like the fact checking matching others as they all use the same source. But the rest like bias can’t be trusted as it’s just their own unscientific methods.
They’re not saying that. How did you summarize 23 words using 39 words, and get the summary wrong?
They’re saying that there is no external professional vouching for MBFC’s conclusions, which is their usual gold standard for things being “reliable.” And that, on top of that, people within Wikipedia have specifically pointed out flaws with how MBFC does things, without any of the qualifications and categories that you added.
I’m trying to summarize the wiki reasoning/what’s in the wiki page about mbfc criticisms
Got it, that does make sense. You should know, though, that Wikipedia on the content side is a different thing from Wikipedia on the talk page side.
People can have nice things to say about a source in their Wikipedia page about the source, on the content side, while there’s still a consensus on the talk page side that the source is unreliable and shouldn’t be used for sourcing claims about other matters on other Wikipedia pages. The big table that I and someone else linked to are good summaries of the consensus on the talk page side, which is what’s most relevant here.