They're a Japanese company that's used to closed console ecosystems. I think they just legitimately hate the idea of a bunch of unwashed randos getting their grubby hands all over their code, especially when it has the potential of eating into their DLC profits. Why would a PC gamer buy red orbs in DMC5 with real fucking money when they could just use CheatEngine, or pay to edit their character in one of the Monster Hunter games when they could just get a mod to do that? I believe things like the nude Chun Li tournament thing or modders making Patreon bank from porn mods for the new RE games also get on their nerves, but it's mostly about protecting their bottom line