Actually in England the rule is the other way around. It is arguably more consistent.

I've noticed that, over time, programmers (including myself) tend to break some punctuation rules. I guess it's because we don't write:

char *foo = "bar;"

The convention in question is actually a technique American typesetters used to keep track of the punctuation. It doesn't exist because it makes sense, but because of a trick of the trade.

Yeah, I run red lights because I dun like them. They're just not me.

Yeah, I hate it when I reorder my quotes and periods and people get killed. No, wait... I don't think that's really a good analogy.

Maybe I slightly exaggerated.