It's not a play on words. This is the section you've been charged under:
Carrying licences and surrender on demand
33. (1) Every driver of a motor vehicle or street car shall carry his or her licence with him or her at all times while he or she is in charge of a motor vehicle or street car and shall surrender the licence for reasonable inspection upon the demand of a police officer or officer appointed for carrying out the provisions of this Act.
When you're stopped, you have to be able to produce your licence, ownership and proof of insurance. Commercial vehicle operators have several other documents to produce as well. The officer isn't disputing that you're licensed, simply that you didn't have your licence with you. He likely did several computer checks to verify you had a licence before charging you. If he had believed you were unlicensed, you would have been charged with "Drive Motor Vehicle No Licence" and received a much larger fine.
I don't see any grounds you can fight it on. Forgetting it at home is not an excuse. The law requires you have the document with you while operating a motor vehicle. There is no truth to the commonly held belief that if you show up to the police station within 24 hours the ticket will be quashed.
I've seen people fight this ticket before and every time the JP simply asks them "Did you give the police officer you licence when he asked you for it?" The minute they say no, they're found guilty.
Your best bet might be to meet with the prosecutor and see if they'll agree to a reduced fine if you plead guilty.