Not exactly a fair comparison. Illegals aren't able to mooch off of most social benefits, so naturally if they're coming here, it's to work and/or to have children become American citizens. Like, international tourists coming to Vegas are more likely to party than the people that live there too, because why else would someone go to the effort of flying there? Additionally, all populations will have some portion of men that are crippled, lazy, excessively dumb, or some combination of the above. Mexico has those too, but they're not coming here when they can live with Mama and Papa and maybe help entertain the nephews and nieces. Our real problem is the number of what are simply inferior human beings, given the good fortune of being born here but not doing anything with that, people whose tax payments will never come close to the amount of social benefits they receive. Illegal immigration has its issues, but it's a perfectly natural response to jobs that pay more than they're worth, and people that are enabled to not work whether due to social services or family allowing them.
EDIT: I didn't click the link until just now, those graphs are a beautiful illustration of how easy the developed middle-class has had it. Now they're finally starting to feel the pressures of competition, and all hell breaks loose. Go China! Go Mexico!