AOG
No...just...
No...
I know it may have been funny to you, but in order for it to have traction humour-wise, it would need to 'speak to the truth' or 'confirm our prejudices'.
Because Muslims are not generally regarded as workshy, the joke failed.
You may have meant it to be humorous, but it went askew.
Joke:
Q. Do you know how the Grand Canyon was formed ?
A. A Scot dropped a penny in a golf hole.
Non-joke:
Q. Do you know how the Grand Canyon was formed ?
A. A Peruvian dropped a penny in a golf hole.
Unless a demographic is (fairly or, in most cases, unfairly) associated with a particular character trait, the joke doesn't work.
But then again, it's easy to say something's a joke once people call you out on it.