There should be many changes, cleaning out the SS number databases, fining employers of illegals, ending all welfare benefits and free health care etc besides just shooting people trying to make their way over. Most important would be demanding the Mexican government reform itself ASAP.
US laws were specifically written to protect transient laborers from unfair labor practices, which were degrading and humiliating for farm workers, both domestic and those who worked via a legal work permit system.
Your initial post mentioned maids and gardeners.Cheap household help or "servants" are not considered a compelling national need and so the federal government does not have a clear cut policy to allow you to create your own class of inexpensive imported household slaves.The USA also does not have specific laws to allow the market economy system to be subverted by illegaly imported laborers to generate additional profit to meatpackers,construction workers, etc.
The farmworker strawman is exactly that, a strawman argument.
Any USA citizen who hires an illegal alien is part of the problem.I will drop a dime to the INS if I suspect your "maid" is illegal.I know some citizens by birth, and a few legal immigrants, who work in household cleaning, or other low skill positions.These are some of our hardest working and most vulnerable citizens.They deserve the full protection afforded by our laws. Employers who think the laws are for someone else,and are hiring illegals to save a few dollars, have no legal or moral excuse or defense.
I am not a fan of unions.But as long as employers, small and large, feel free to ignore the laws of the USA,in a shortsighted search for temporary profit, I can not call for their abolishment.
BS, they break the law to increase their profit margin.
There are many farmers that use H2A visa holders and can compete in the market place. It's not about wages, it's about profit.