Fundamentally, HOI4 is just a shit game. The Focus Tree system is basically shitty prescripted railroading encoded into an actual core mechanic, and for about 80% of the game litterally all you do is just sit around with your finger up your ass and either wait for things to happen or watch the game play itself for you, with the remaining 20% being retarded nonsense spamclick micro to fucking Instant Transmission a Motorized division around enemy divisions for free encirclement or to fucking Rommel your way to enemy capitals.
Furthermore, the game runs like shit, has assloads of bad, half-baked DLC that add less content than script-kiddie tier mods...
And then there's that. The Modding Scene. A den of insufferable autists so retarded that they committed ideological necromancy at least twice and think their poorly-written stealth-VNs are some sort of world-changing art that can save the Earth from the clutches of The Alt-Right Death Squads.
Even if Hearts of Iron wasn't a dog turd of a videogame, with a fanbase that rivals goliaths like Undertale or heyday-MLP in the autistic shitter department, it would still be hard to not despise it. As it is, burn it, burn the fans, and burn Paradox too, fuckers never make anything worth buying anyway.