Why do these programs always seem to target the worker, but not the employer? Enforcement of illegal immigration always seems to have the immigrants arrested an

Why do these programs always seem to target the worker, but not the employer? Enforcement of illegal immigration always seems to have the immigrants arrested and deported, but what about the people who hired the illegal workers? H-1B visa holders get blamed for "competing against permanent residents" but where's the blame for companies who hire H-1B workers over American citizens? We live in a capitalist economy which follows pretty simple supply and demand curves. Where there is a demand (cheap labor) there will always be a supply (even if it's the black market). Arresting sex workers doesn't stop people from hiring them, and arresting drug users doesn't stop the dealers. Immigrants don't come to the US because it's fun or easy, there come here because there are companies willing to hire them, legally or not. So if there are too many H-1B holders competing with Americans, why not make it harder for companies to hire them over an equally qualified American, or punish the company for abusing the visa system just to get cheaper labor? Same with illegal immigration, why not fine or shut down businesses that hire illegal immigrants? You say it's not pretty it's just reality and I accept that reality... but it's also needlessly cruel to punish job seekers and not the companies who are enticing them to come here.