Why were I able to "check" the "disabled" checkbox on the live site and the data was successfully uploaded to the server

So I just visited one site, where it had the "disabled" checkbox

<input type="checkbox" name="name" checked="checked" disabled="disabled">

It couldn't be checked via mouse, so I decided to uncheck it via jQuery. Opened the console and wrote:

$('input[name="name"]').attr('checked', false);

It got unchecked. I thought, well, maybe it's just for me unchecked, but server will still get data from it as if it's checked.

So I uploaded my form and to my surprise the server behaved as if checkbox was unchecked.

Why?