I've been thinking about this post, and I'm sure all the other commentators are right, much of this is the consequece of lockdown, but if they feel so strongly about littering, would there be value in using that as a metaphor for when they're behaving badly? Point out that talking when someone else is daoing something is the equivalet of dropping a packer of crisps on a pathway, etc.

I'm sorry that this is spoiling Brownies for you.