There are a few references that say glyphosate doesn't bioaccumulate well due to the chemical's "ionized state, its low octanol-water partition coefficient"[1]. However there are others that suggest glyphosate may bioaccumulate in biofilm consuming invertebrates, where biofilms concentrate glyphosate and prevent the chemical from being retained in surrounding water[2].
Personally, these concepts are newer to me and I'm not sure what to make of it all yet.
Maybe a hot take, but as others have identified, these violent outbreaks are at least in part due to social isolation, which may have something to do with lifestyle, city layout, and ease of access to public parks/things to do. Cities in the US have been set up to support cars, creating widely spread out and large landscapes, inconvenient for those who don't drive. Finding niche groups to fit in with on the internet has become easier, but irl in the US, much harder. This is independent of age group, but obviously impacts kids in a huge way. IMO, we need more places for people in communities to get together and just talk about things, engage in continued education, and have fun. Would be interesting to see if there's a correlation between after school programs, or proximity of public spaces and violence.
Personally, these concepts are newer to me and I'm not sure what to make of it all yet.
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6827263/ [2] https://www.biorxiv.org/content/10.1101/2020.08.03.234856v1....