You have identified an important issue, but there is one complication: CPP contributions are not the same thing as deposits into an individual investment account.
Under the salary scenario, the employee contributes $2,163 and the corporation contributes another $2,163 to CPP, so a total of $4,326 is indeed being contributed to CPP as a result of that employment. However, that does not mean the employee has a personal CPP account containing $4,326. CPP is a social-insurance pension system, and the contributions help determine the employee's future pension entitlement rather than becoming an individually owned investment balance.
Therefore, putting only $2,163 into savings under the dividend scenario does not create a perfect apples-to-apples comparison. But simply putting $4,326 into a private account is not perfectly equivalent either, because a private investment account and CPP provide different benefits and risks.
There are also other important differences between salary and dividends. Salary generally creates RRSP contribution room and involves CPP contributions, while dividends generally do not. The corporation's tax treatment also differs, and the individual's tax treatment depends on the type and amount of dividend.
So I would not make the decision based solely on the apparent $2,163 CPP savings in this example. The proper comparison is the total after-tax economic benefit of each alternative, including CPP benefits, RRSP room, corporate taxes, personal taxes, and the individual's retirement objectives.
Also, because the article is from 2012, its specific tax rates, CPP limits, and dollar amounts should not be used for a current decision without updating them.