Why does WordPress load jQuery in my header instead of footer?

It is true that browsers choke on scripts, so generally it is best to put scripts in the footer to prevent the whole page being delayed. So putting jquery in the footer also makes sense.

However, WordPress websites usually have plugins that may also include jquery scripts, which they may load in the header without you knowing it. As long as jquery itself is not loaded, because you’ve put it in the footer, those scripts won’t work. If those scripts control the looks of the page, you may have some very weird looking page while the browser is waiting for jquery.

So, there you have it: put jquery in the head of your WP site, because others may assume it’s there.