They say a lot of things about employment contracts. Most of it isn't applicable in Canada, but especially Ontario. If an employment contract violates any legislation, regulations, employment standards, or general fair labor practices, the courts won't uphold it. Even the ever so popular restricted covenants such as non-compete clauses get labelled as a "restraint on trade", and are very rarely upheld by any judge in Ontario.
Unless you hired a lawyer to review it before signing, your employer can show they are providing fair additional compensation for any clauses they want you to agree on (which means more then just getting the job), and your non-compete comes with a golden parachute to keep you home. Your contract is worth less then the paper it's printed on once it hits an Ontario judge.