Unlike you, and all your conspiracy theorist friends, fact checkers provide sources for their claims, something that conspiracy theorists don't do. Presenting a YouTube video, or a Facebook post doesn't count a reputable source. Moreover, you can check the sources legitimacy yourself, since everything is listed there, publicly to check for yourself.
to be fair, we shouldn't trust only one source just because it's fact-checked. for the best practice, gather the same news reports from multiple sources, regardless of fact-checking or the reliability of its source. if the fact-check only contains primary sources (or sources coming from allies but nothing from opposites just because they aren't reliable, especially regarding conspiracies), they too could be a conspiracy.
assuming there are two fact-checkers who have a contrasting conclusion, both get reliable sources, who are we going to trust?
for example,
this article about covid vax deaths i have linked before also contains numerous sources on their claims. no matter how misrepresented to you, under your logic, this too should be considered a fact-check.