Assuming the linked article is accurate, there are 120k overtays from Canada, compared to 47k Mexicans. That number pales in comparison to illegal border crossings from Mexico. If they caught 415k trying to cross during that year, the actual number that crossed far exceeded 415k. That means illegal immigrants with no background checks (in fact, no checks whatsoever) coming over the southern border are a way bigger problem by orders of magnitude than illegal immigration through visa overstays. If there is any doubt, reference the number of illegal Canukistanis living here compared to the Mexicans. Are there close to 15 million Canucks living here illegally?
Personally I'm all for a sound policy that looks at all aspects -- not just a physical southern border, but a better process for legal immigration, better information on everyone that enters (to make sure they leave), better processes to check whether someone is a legal worker or not (to prevent hiring by employers of anyone here not legally) and on and on.