They are doing potential harm to the millions of immigrants who want to come to the country legally. Many of whom wait years to get their visas and get work.

They are undermining legal immigrants.

My preference would be a system such as Singapore, Japan, Australia, Canada, etc. where they favor people whose skills are in short supply at home. Make it easier to hire high demand low availability skills as well as seasonal workers legally while simultaneously making it very hard to hire undocumented workers in order to encourage legal pathways.