The "age of criminal responsibility" is extremely misleading. There is no uniform "age of criminal responsibility" in the US, each state is different and each law is different, and the site you posted fully acknowledges that[1]. Prosecutors also have a very heavy amount of leeway in this realm.
[1] DEFINITION: The age at which a person is no longer excluded from criminal liability. The lowest age is indicated for countries where there isn’t a single age limit, for example where different states have different regulations (such as the USA) or there is different limits for boy and girls (such as in Iran). The spectrum is specifically wide for the USA and Mexico (both 6-12 years). Several US states do not stipulate any minimal age for criminal responsibility at all.
At no point whatsoever is a 6 year old criminally responsible for anything - and you can tell, because they're 6. This is what a 6 year old look like? [1] This feels apologist - prosecutors should have zero leeway in this matter. States where there isn't one are even worse IMO.
Editing since I can't reply: I may have misread your reply to mine, I reacted because in my mind, that there's a range or discretion is irrelevant because it's so far out there in the first place. Cleaned it up to be less pointed, to better line up with my intent and hopefully yours.
Excuse me? Please read the comment you are replying to; I did not say a six year old should be criminally responsible for anything or anything of the sort.
[1] DEFINITION: The age at which a person is no longer excluded from criminal liability. The lowest age is indicated for countries where there isn’t a single age limit, for example where different states have different regulations (such as the USA) or there is different limits for boy and girls (such as in Iran). The spectrum is specifically wide for the USA and Mexico (both 6-12 years). Several US states do not stipulate any minimal age for criminal responsibility at all.