If you really believe that fact checks were "rarely if ever" used before or after Trump's term, I can't help but wonder if your exposure to them is mainly through articles about "biased fact checks" on media like NYT or Fox - it stands to reason that there'd be a lot more of them showcased when Trump was the main source of widely publicized false information.
"Fact Checking" was most definitely not a common, headline news tagline until Trump.
If you genuinely cant see the problem with intelligence agents pushing their weight around for political sway, then theres no sense in engaging with your arguments