here's Mazin's explanation: https://variety.com/2023/tv/news/last-of-us-clickers-flour-theory-game-changes-explained-1235495180/
Yeah, I didn't find it weird at all. If anything, just unsettling. The fungus communicates to itself, so that runner knew she was infected. The fungus was attaching itself to her to connect and spread even more.
It seems like they were inspired by the fairly recent discovery of Mycorrhizal Networks. In forests trees use the fungus that grows on their roots that is connected to other trees to send messages to eachother via electrical impulses. They also use fungal networks to share water and nutrients with each other as well. This theory wasn't fully out there when the game first came out so its cool they are incorporating it.
Also on the subject of video games people wouldn't think could work as an adaptation that i want an adaptation of: Give me a Stardew Valley show. I think people who have never played will be shocked at how much depth there is and how weird/quirky it is. It would be like if David Lynch made Little House on the Prairie or something. So much potential.