Probably that ctrl+q is the historical cross-platform standard for quitting. Also you may have missed that not all keyboard layout are QWERTY.
QWERTZ also has Q next to W.
I should know, I'm using a QWERTZ keyboard. But those are not all keyboard layouts: QÜERTY, ÄWERTY, QZERTY, DVORAK, BÉPO, JCUKEN, WORKMAN, ŪGJRMV, MALTRON, etc.
Then there are the asian and middle east that do not even use the same alphabet. Though those may use the QWERTY as an underlying layout for compatibility.
[1] https://addons.mozilla.org/en-US/firefox/addon/disable-ctrl-...