The logic isn't flawed, your priors are. You're assuming that people are constantly on a cycle of charging their battery to the limit, running it down low, and then charging it again. If you mostly play docked or with a charger plugged in then capping the battery at around 80% prolongs the battery runtime for when you do turn the limit off and want to use the full battery.
If you mostly play fully charged and stationary, then lowering the charge limit means you have more future opportunities to experience the fully battery runtime when you disable the setting.
I ran a microbiology lab that specifically tested for food borne illness causing bacteria.
Here's a very recent attempt to assess the safety of cold brew coffee coming out of UGA. https://newswire.caes.uga.edu/story/10365/cold-brew-coffee.html
These findings line up with earlier work such as this paper doing a general analysis of cold brew coffee and this Canadian government report on detected food borne pathogens in cold brew coffee..
The consensus I'm seeing is that cold brew coffee, especially when kept cold, is not a great environment for most food borne illness causing pathogens to thrive. Bacillus cereus and potentially botulism would have been more accurate choices.