Technically true, but beside the point. Mexico actively assists Central Americans as well as their own citizenry to take advantage of our lax laws and loopholes, and then benefits financially in the process to the tune of billions of dollars annually. Best estimates are that we now have 30 to 50 million illegal aliens in this country.
Mexico is a very big part of the problem. Last I checked, our prison population was 15% Mexican nationals, that is, citizens. This and a host of other data make me think that anything south of the border presents huge problems for the US, none of which can be fixed via US-taxpayer solutions applied in those countries, and certainly not by admitting people from there into the US. To put it kindly, it is past time to expel them all and bar the door.