First of all, why are you saying we "arbitrarily" decided to make undocumented immigration illegal? Simply letting in anyone who felt like it in the modern day would most likely ruin the economy, and homeless/unemployed rates would skyrocket as the ratio of people to jobs became even more unbalanced. Having open borders would also be a huge security risk, as many immigrants (especially ones who can't get in legally) come from countries that have more violence/gang violence, crime, and terrorism than other countries. This could easily act as a disguise for the people who would do such things. Another reason is that it would offset the voting/political party balance, which is around 50/50 at the moment I believe. Since democrats want to let them in, when they get in, they would vote democrat, in order to keep the ones in power who are keeping them in the country. In the same way, democrats would vote to keep the immigrants in, which would help keep them in power. I know that's not a problem to you, but if you look at it without either of our political biases, it still offsets the balance and would most likely drastically change America, for better or for worse.
I agree with you about it being immoral of companies to take advantage of them, but again, they sort of brought it upon themselves by immigrating here illegally. We shouldn't have to take in everyone who needs refuge just because we feel bad for them. It's not our place to help everyone in the entire world. Shouldn't their own governments be working to better themselves and help out their own population?
And in response to you aggressively saying I better not have committed any crimes, otherwise no, I haven't. I'm not even 15 yet. Yeah, go ahead, make fun of me, but it's true. You probably won't believe me, and even if you do, you probably have almost no chance of listening to anything I say, but I'm just putting that out there.